US005366526A United States Patent (19) 11 Patent Number: 5,366,526 Ellison-Hayashi et al. 45 Date of Patent: Nov. 22, 1994

54 METHOD OF ABRADING WITH BORON tals:', Stanford Research Institute, Menlo Park, Calif., SUBOXIDE (BXO) AND THE BORON Jan., 1963. SUBOXIDE (BXO) ARTICLES AND H. Tracy Hall and Lane A. Compton, "Group IV Ana COMPOST ONUSED logs and High Pressure, High Temperature Synthesis of 75 Inventors: Cristan Ellison-Hayashi, Salt Lake B2O’, Inorg. Chem. 4 (1965) 1213. City, Utah; George T. Emond, W. C. Simmons, "Progress and Planning Report on Southington, Conn.; Shih Y. Kuo, Boron Suboxide B60', Air Force Materials Labora Salt Lake City, Utah tory, Mar., 1968. H. Wrerheit, P. Runow, and H. G. Leis, "On 73) Assignee: Norton Company, Worcester, Mass. Boron-Suboxide Surface Layers and Surface States of 21 Appl. No.: 51,114 B-Rhombohedral Boron:”, Phys. Stat. Sol. (a) 2, K125 (1970). 22 Filed: Apr. 21, 1993 E. V. Zubova, K. P. Burdina, "Synthesis of B6O Under Pressure', Dokl. Akad. Nauk. SSR, 197 (5) (1971) Related U.S. Application Data 1055-1056. 63 Continuation-in-part of Ser. No. 920,357, Jul. 28, 1992, which is a continuation-in-part of Ser. No. 729,467, Jul. (List continued on next page.) 12, 1991, Pat. No. 5,135,892. 51) int. Cl...... C09K3/14 Primary Examiner-Wayne Langel 52 U.S. C...... 51/307; 51/309 Attorney, Agent, or Firm-Brian M. Kolkowski 58 Field of Search ...... 423/278; 501/1; 51/281 R, 307, 309 57 ABSTRACT 56 References Cited A method of removing material from a surface compris U.S. PATENT DOCUMENTS ing abrading a surface comprising the step of abrading a 1,105,388 7/1914 Weintraub ...... 423/278 surface with an abrasive tool or an abrasive powder 3,660,031 5/1972 Holcombe, Jr. et al. . ... 423/278 comprising a boron suboxide (BxO) composition, 3,816,586 6/1974 Goosey ...... 264/332 wherein during the abrading step the boron suboxide 5,135,892 8/1992 Ellison-Hayashi ...... 501/1 (BxO) composition is maintained at low temperatures. The abrasive which is from the boron suboxide (BxO) FOREIGN PATENT DOCUMENTS family of compounds exhibits an unexpectedly high 574609 4/1959 Canada ...... 423/278 quality of abrading comparable with the highest quality OTHER PUBLICATIONS particulate natural and synthetic diamond, which has a R. R. Pasternak, "Crystallographic Evidence for the hardness about double that of the boron suboxide (BxO) Existence of B7O, Acta Cryst.” 12 (1959), 612. of the present invention. S. LaPlaca, B. Post, "The Boron Carbide Structure Further, the invention includes a lapping and polishing Type', Planseeberichte Fur Pulvermetallurgie, Bd. 9, powder and lapping slurry wherein the powder is made 1961. from a dense, finely crystalline boron suboxide material H. F. Rizzo, W. C. Simmons, and H. O. Bielstein, "The with a Knoop hardness KHN100 of at least about 2800 Existence and Formation of the Solid B6O, Journal of kg/mm2 and preferably at least 3800 kg/mm2. the Electrochemical Society,” Jan. 1963. F. A. Halden, R. Sedlacek, “Growth and Evaluation of Boron Suboxide and Zirconium Dioxide Single Crys 18 Claims, 14 Drawing Sheets O5

DAMOND

O3 BORON SUBOXIDE O.2 O. BORON CARBIDE

3s 3. 3.6 4. 4.6 5. 5.6 6. 6.6 7. HARDNESS x IOOO(kg/mm *2) 5,366,526 Page 2

OTHER PUBLICATIONS V. S. Makarov and Ya. A. Ugai, "Thermochemical C. E. Holcombe, Jr., and O.J. Horne, Jr., “Preparation Study of Boron Suboxide B6O”, Journal of the Less of Boron Suboxide, B60', Journal of the American Common Metals, 117 (1986), 277-281. Ceramic Society-Discussions and Notes, vol. 55, No. 2 C. Brodhag and F. Thevenot, "Hot Pressing of Boron (1971) 106. Suboxide B1202', Journal of the Less Common Metals, D. R. Petrak, R. Ruh, B. F. Goosey, "Preparation and 117 (1986), 1-6. Characterization of Boron Suboxide', National Bureau of Standards Special Publication 364, Solid State Chem Tadashi Endo, Tsugio Sato, Masahiko Shimada, "High istry, Proceedings of 5th Materials Research Sympo pressure synthesis of B2O with diamond-like struc siums, issued Jul. 1972. ture”, Journal of Materials Science Letters 6(1987), W. H. Rhodes, A. J. DeLai, “Research on Develop 683-685. ment and Fabrication of Boron Suboxide Specimens', David Emin, “Icosahedra Boron-Rich Solids', Physics AVCO Corp., prepared for Air Force Materials Labo Today, Jan., 1987. ratory, Aug., 1972. R. R. Petrak, Robert Ruh, and G. R. Atkins, “Mechani Andrzej Badzian, "Superhard Material Comparable in cal Properties of Hot-Pressed Boron Suboxide and Hardness to Diamond'', Appl. Phys. Lett. 53(25), 19 Boron”, Ceramic Bulletin, vol. 53, No. 8 (1974), Dec. 1988. 569-573. W. E. Moddeman, A. R. Burke, W. C. Bowling and D. P. M. Bills and D. Lewis, "Non-stoichiometry of Boron S. Foose, “Surface Oxides of Boron and B12O2 as Deter Suboxide (B6O)', Journal of the Less Common Metals, mined by XPS' Surface and Interface Analysis, v. 14 45 (1976) 343-345. n5, May, 1989, pp. 224-232. U.S. Patent Nov. 22, 1994 Sheet 1 of 14 5,366,526

F G. U.S. Patent Nov. 22, 1994 Sheet 2 of 14 5,366,526

O5 DAMOND O4 O3 BORON SUBOXDE O.2 O. BORON CARBIDE

3s 3. 3.6 4. 4.6 5. 5.6 6. 6.6 7. HARDNESS x IOOO(kg/mm *2) F G. 2

O8 BORON O7 sk SUBOXIDE

DAMOND O4CARBDEBORON O

2.6 3. 3.6 4. 4.6 5. 5.6 6. 6.6 7. HARDNESS x IOOO (kg/mm2) F. G. 3 U.S. Patent Nov. 22, 1994 Sheet 3 of 14 5,366,526

2.

(f) (f) C 1.5 BORON DAMOND s SUBOXDE S9 | k O5 BORON CARBIDE O 2.6 3. 3.6 4. 4.6 5. 5.6 6. 6.6 7. HARDNESS x IOOO (kg/mm2)

2.5 k BORON

2 SUBOXIDE

(f)5 .5 DAMOND 9 s SSK O.5 O 2.6 3. 36 4. 4.6 5. 5.6 6. 6.6 7. HARDNESS x IOOO(kg/mm2) F. G. 5 U.S. Patent Nov. 22, 1994 Sheet 4 of 14 5,366,526

3 2.5 DAMOND (f)f5 2 C 5 SUBOXIDE s se* O.5 BORON CARBDE O 2.6 3. 3.6 4. 4.6 5. 5.6 6. 6.6 7. HARDNESS x IOOO (kg/mm *2)

5 BORON 4. * SUBOXIDE 2 C 3

s DIAMOND

e BORON CARBIDE k

O 2.6 3. 3.6 4. 46 5. 5.6 6. 6.6 7. HARDNESS x IOOO (kg/mm2) F. G. 7 U.S. Patent Nov. 22, 1994 Sheet 5 of 14 5,366,526

U.S. Patent Nov. 22, 1994 Sheet 7 of 14 5,366,526

U.S. Patent ov. 22, 1994 Sheet 10 of 14 5,366,526

U.S. Patent Nov. 22, 1994 Sheet 11 of 14 5,366,526

O'OL). Ok (Sdo) ALISN3N

U.S. Patent Nov. 22, 1994 Sheet 3 of 14 5,366,526

5,366,526 1. 2 under a 100 gram load (VHN100) of 3,820 kg/mm2 and METHOD OF ABRADING WITH BORON a density of 2.60 grams/cc. The material is described as SUBOXIDE (BXO) AND THE BORON SUBOXIDE highly refractory, and suitable for use on surfaces sub (BXO) ARTICLES AND COMPOSITION USED ject to abrasion, e.g., grinding wheels, drill bits, ma 5 chine tools, etc., and in structures employed in high CROSS-REFERENCE TO RELATED temperature applications. APPLICATIONS In U.S. Pat. No. 3,816,586, a method of fabricating This Application is a continuation-in-part of applica boron suboxide products is disclosed. According to this tion Ser. No. 07/920,357 filed Jul. 28, 1992, pending, patent, a mixture of elemental boron and boron oxide is which is a continuation-in-part of Ser. No. 07/729,467 O cold pressed in a tantalum lined metal die. After the filed Jul. 12, 1991, now U.S. Pat. No. 5,135,892 both of pressure on the compacted mixture is released, it is which are hereby incorporated by reference. coated with a mixture of boron nitride and boron oxide, and is subjected to a second pressing step while heating BACKGROUND OF THE INVENTION at a temperature sufficient to melt the boron oxide in the 1. Field of the Invention 15 compacted mixture. This is followed by a cooling step The invention relates to a method of removing mate rial from a surface using an abrasive tool or powder and another hot pressing step. The boron suboxide comprising a boron suboxide (BxO) composition. The product made by this method is reported as being a invention further includes the boron suboxide (BxO) smooth, sound boron suboxide article, free of flaws and composition and articles made from the boron suboxide 20 contaminants, and suitable for a variety of applications. (BxO) composition used in lapping and polishing, hon Upon analysis, the boron suboxide product gave 80.1 wt ing, bonded abrasives, coated abrasives, wire sawing, % boron and 19.9 wt % oxygen which corresponds to abrasive flow machining, abrasive jet machining, abra the stoichiometry of B6O. It was also reported as having sive waterjet machining and fixed abrasive lapping. The a density of 2.60 grams/cc and a Knoop hardness under invention further relates to a novel boron suboxide 25 a 100 gram load (KHN100) of 3000 kg/mm2. (BxO) material and to a method for its preparation. Other reports on methods of preparing boron subox 2. Technology Review ide and the properties of this material are the following: A great deal of research has been devoted to develop 1. R. R. Pasternak, “Crystallographic Evidence for ing synthetic superhard materials which have hardness the Existence of B7O:, Acta Cryst. 12 (1959), 612; values approaching that of diamond. The best known of 30 2. S. LaPlaca and B. Post, "The Boron Carbide Struc these synthetic superhard materials is cubic boron ni ture Type', Planseeberichte Fur Pulvermetallurgie, Bd. tride (CBN). Other very hard binary and ternary com 9, 1961; pounds made from light elements such as boron, nitro 3. H. F. Rizzo, W. C. Simmons, and H. O. Bielstein, gen, oxygen, aluminum, silicon and phosphorous may “The Existence and Formation of the Solid B6O", Jour exist. Among these, the compounds C3N4, BNC, BPN, 35 nal of the Electrochemical Society, Jan. 1963; B4C and BP may be mentioned. Another of these com 4. F. A. Halden and R. Sedlacek, "Growth and Eval pounds which has been reported as having high hard uation of Boron Suboxide and Zirconium Dioxide Sin ness values is boron suboxide (BxO). gle Crystals', Stanford Research Institute, Nenlo Park, Boron normally has a valence of 3 and reacts with Calif., January 1963; oxygen to form boron oxide having the stoichiometric 5. H. Tracy Hall and Lane A. Compton, "Group IV formula B2O3. Under suitable conditions, boron may Analogs and High Pressure, High Temperature Synthe react with oxygen and form compounds in which boron sis of B2O, Inorg. Chem. 4 (1965) 1213; exhibits a valence less than 3. Powders of nominal com 6.W. C. Simmons, "Progress and Planning Report on position B3O, B40, B60, B7O, B80, B120, B130, and Boron Suboxide B60', Air Force Materials Labora B18O have been reported as being formed by reacting 45 elemental boron (B) with boron oxide (B2O3) under tory, March, 1968; suitably high pressure and temperature conditions. For 7. H. Wrerheit, P. Runow, and H. G. Leis, "On Bo purposes of this disclosure, the term "boron suboxide ron-Suboxide Surface Layers and Surface States of (BxO)” refers to boron/oxygen binary compounds B-Rhombohedral Boron”, Phys. Stat. Sol. (a) 2, K125 wherein boron has a valence less than 3. Since different 50 (1970); varieties of boron suboxide have been reported by oth 8. E. V. Zubova and K. P. Burdina, “Synthesis of ers, boron suboxide (BxO) will be generally designated B6O Under Pressure', Dokl. Akad. Nauk. SSR, 197 (5) with the chemical formula B.O. (1971) 1055-1056; The formation of boron suboxide (BxO) and a de 9. C. E. Holcombe, Jr., and O. J. Horne, Jr., "Prepa scription of its properties have been extensively re 55 ration of Boron Suboxide, B60', Journal of the Ameri ported in the literature. Most of the reports in the litera can Ceramic Society-Discussions and Notes, Vol. 55, ture attribute the formula B6O prB7O to the boron No. 2 (1971) 106; suboxide (BxO) being investigated. In some cases, the 10. D. R. Petrak, R. Ruh, and B. F. Goosey, "Prepa boron suboxide (BxO) formed and the material being ration and Characterization of Boron Suboxide', Na investigated may consist of more than one phase. In tional Bureau of Standards Special Publication 364, U.S. Pat. No. 3,660,031, a method of preparing a boron Solid State Chemistry, Proceedings of 5th Materials suboxide material is disclosed. According to this patent, Research Symposiums, issued July 1972; the boron suboxide material is formed by reducing zinc 11. W. H. Rhodes and A. J. DeLai, "research on oxide with elemental boron at a temperature in the Development and Fabrication of Boron Suboxide Spec range of 1200-1500 C. The boron suboxide (BxO) 65 imens', AVCO Corp., prepared for: Air Force Materi produced by this method is reported as having the for als Laboratory, August, 1972; mula B7O. It is also characterized as having an average 12. R. R. Petrak, R. Ruh, and G. R. Atkins, "Mechan hardness value as measured with a Vickers indentor ical Properties of Hot-Pressed Boron Suboxide and 5,366,526 3 4. Boron’, Ceramic Bulletin, Vol. 53, No. 8 (1974), Grinding, lapping, polishing and cutting is carried out 569-573; on materials such as metals, ceramics, glass, plastic, 13. P. M. Bills and D. Lewis, "Non-stoichiometry of wood and the like, using bonded abrasives such as Boron Suboxide (B6O)”, Journal of the less Common grinding wheels, coated abrasives, loose abrasives and Metals, 45 (1976) 343-345; 5 abrasive cutting tools. Abrasive grains, the cutting tools 14. V. S. Makarov and Ya. A Ugai, "Thermochemi of the abrasive process, are naturally occurring or syn cal Study of Boron Suboxide B6O”, Journal of the Less thetic materials which are generally much harder than Common Metals, 117 (1986), 277-281; the materials which they cut. The most commonly used 15. C. Brodhag and F. Thevenot, "Hot Pressing of abrasives in bonded, coated and loose abrasive applica Boron Suboxide B12O2', Journal of the Less Common 10 tions are garnet, alpha alumina, silicon carbide, boron Metals, 117 (1986), 1-6; carbide, cubic boron nitride, and diamond. The relative 16. Tadashi Endo, Tsugio Sato, Masahiko Shimada, hardness of the materials can be seen from the following "High-pressure Synthesis of B2O with Diamond-like table: Structure', Journal of Material Science Letters 6 (1987), 683-685; 15 17. D. Emin, “Icosahedra Boron-Rich Solids', Phys Material KHN100 Hardness ics Today, January, 1987. garnet 1360 a-alumina 2100 18. A. Badzian, "Superhard Material Comparable in silicon carbide 2480 Hardness to Diamond”, Appl. Phys. Lett. 53(25), 19 boron carbide 2750 Dec. 1988; 20 cubic boron nitride 4500 19. W. E. Moddeman, A. R. Burke, W. C. Bowling diamond (monocrystalline) 7000 and D. S. Foose "Surface Oxides of Boron and B12O2 as Determined by XPS' Surface and Interface Analysis, The choice of abrasive is normally dictated by eco Vol. 14 n5, May, 1989, 224–232. nomics, finish desired, and the material being abraded. All of the aforementioned patents and publications 25 The abrasive list above is in order of increasing hard are hereby incorporated by reference. ness but it is also coincidentally in order of increasing These publications and patents are in agreement that cost with garnet being the least expensive abrasive and boron suboxide compounds can be produced according diamond the most expensive. to the following chemical equation: Generally, a soft abrasive is selected to abrade a soft 30 material and a hard abrasive to abrade harder types of (3x-2)B-B2O3-)-BO (1) materials in view of the cost of the various abrasive at moderately high pressures (e.g., 1,000 to 6,000 psi) materials. There are, of course, exceptions such as very and moderately high temperatures (e.g., 1400 to 2200 gummy materials where the harder materials actually 35 cut more efficiently. Furthermore, the harder the abra C.). The specific form of BO actually produced de sive grain the more material it will remove per unit pends on the process conditions and the ratio of elemen volume or weight of abrasive. Superabrasive materials tal boron to boron oxide loaded into the reaction cell. include diamond and cubic boron nitride, diamond is Alternatively, boron suboxide compounds may be pro the hardest known material, and cubic boron nitride is duced according to the following chemical equation: the second hardest. One skilled in abrasive technology would expect an abrasive material with similar proper B--MO-BO-M (2) ties to perform consistently in relation to other materials wherein M=Mig or Zn, at temperatures ranging from in a variety of applications (e.g., diamond and cubic 1200° C. to 1500 C. without applied pressure. Depend boron nitride perform similarly relative to each other in ing on the starting proportions of boron and metal ox 45 grinding, lapping and cutting applications). ide, the formula B6O has been attributed most fre We have found no indication in the literature that quently to the boron suboxide compound formed, al boron suboxide (BxO) has been used in the abrasives though some researchers report the formation of B7O field. Boron suboxide (BxO), however, if used would be and other boron/oxygen compounds. expected to perform as an abrasive in a manner relative Generally, the hardness and density values reported 50 to the hardness used. With no researcher(s) having for boron suboxide in all of the aforementioned publica reported a KHN100greater than 3600 kg/mm2 for boron tions have been in good agreement. Average KHN100 suboxide, the boron suboxides (BxO) with hardnesses values of 3400 to 3600 kg/mm2 were reported by Sim less than 3600 kg/mm2 would have been expected to mons, and KHN100 values of 3400 to 3500 kg/mm2 were have abrasive properties similar to those of other abra reported by Petrak et al. The KHN100 value reported in 55 sives with similar hardnesses. Furthermore, boron sub U.S. Pat. No. 3,816,586 is somewhat anomalous and this oxide (BxO) would have been expected to perform, may be due to the presence of another phase in addition relatively the same in all bonded, coated, cutting and to B6O. In any event, none of the researchers have loose abrasive applications. reported a KHN100 greater than 3600 kg/mm2 for boron Conventionally, boron suboxides because of their suboxide. The densities reported by these researchers 60 lower hardness were not considered for abrasive appli have been from 99.5 to 100% of the theoretical value. cations. While many compounds in the boron suboxide Furthermore, based on crystallographic data, most of family (BxO) family are known, what is unknown is the the researchers have ascribed a rhombohedral unit cell use of boron suboxide (BxO) in articles manufactured at to the boron suboxide that was produced. temperatures below which boron suboxide degrades, Recent crystallographic studies of B6O and B70 have 65 boron suboxide (BxO) abrasive applications performed revealed that both possess the same crystal structure. at temperatures below which boron suboxide (BxO) This indicates these are the same defect phase and in degrades, and the superior unexpected results achieved clude all intermediate compositions. in these applications. 5,366,526 5 6 Further, while the reported hardness values of boron tion 3 and was not adjusted to compensate for its lack of suboxide (BxO) are quite good, it would be desirable to purity. Transmission electron microscopic examination produce a superhard form of boron suboxide (BxO) of this harder material reveals a more defect-free struc having a hardness value which more closely approaches ture than previously reported forms of B6O. An alter that of diamond which ranges from KHN100 of 6000 to nate method of producing B6O of high hardness is to 9000 kg/mm2. More particularly, because the raw mate use pure raw materials and separately add a suitable rials which form boron suboxide are inexpensive and quantity of the desired sintering aid. Other materials the process is relatively simple, it would be desirable to such as Ca and Y are also expected to act as sintering produce a superhard form of boron suboxide which has aids. an average KHN100 hardness value of at least about 10 In a further alternate method of producing superhard 3800 kg/mm2, and preferably in the range of about B6O, it is possible to mix substantially pure B2O3 with 4000-4500 kg/mm2. substantially pure B without the inclusion of any sinter SUMMARY OF THE INVENTION ing aid. It should be understood that an outer layer of The invention is a method of removing material from boron oxide may form on the surface of the boron parti a surface comprising the step of abrading a surface with 15 cles. When used in the context of this alternative an abrasive tool or powder comprising a boron subox method of producing superhard boron suboxide, the ide (BxO) abrasive composition wherein during the terms "substantially pure' and "essentially pure' boron abrading step degradation of the boron suboxide abra disregard this oxide layer and are meant to convey that sive composition is minimized. The abrasive which is no sintering aid is present. In accordance with this alter from the boron suboxide (BxO) family of compounds 20 nate method, the boron particles are extremely small exhibits an unexpectedly high quality of abrading com (average particle size of less than 1 micron) and an parable with the highest quality particulate natural and excess of boron powder is mixed with the boron oxide synthetic diamond, which has a hardness about double in order to compensate for the extra oxygen which is that of the boron suboxide. present in the oxide layer. The superhard BxO made by Further, the invention includes the use of the boron 25 this method is homogeneous and has an average grain suboxide (BxO) compositions in a fluid vehicle, the size of about 1-5 microns in comparison to an average boron suboxide (BxO) composition containing abrading grain size of 18-40 microns if made by the other meth slurry, articles of bonded boron suboxide (BxO) bonded ods described above. Material having an average grain at low temperatures, articles of coated boron suboxide 30 size of less than 5 microns will be referred to herein as (BxO), boron suboxide (BxO) abrasive cutting tools "fine grain' form of boron suboxide, while the material manufactured at low temperatures and the boron subox having an average grain size of 18-40 microns will be ide (BxO) compositions used in this abrading method. referred to herein as "large grain” boron suboxide. The boron suboxide (BxO) used in these applications BRIEF DESCRIPTION OF THE DRAWING can either be produced by methods known in the art, or 35 for the preferable higher hardnesses, a new boron sub FIG. 1 illustrates the specially designed cell which is oxide (BO) material is provided which comprises at used to produce the novel form of boron suboxide. least 95% by weight of B6O and has an average FIG.2 graphically shows the predicted or theoretical KHN100 hardness value of at least about 3800 kg/mm2. lapping performance on 4140 steel of the invention Preferably, the new boron suboxide material has an BxO, diamond, and boron carbide abrasives, based on average KHN100 hardness value above about 4000 their Knoop hardnesses (KHN100). kg/mm2, typically about 4250 kg/mm2, which is well FIG.3 graphically shows the actual lapping results of beyond the average hardness values previously re BxO, diamond, and boron carbide, lapping 4140 steel. ported for any form of boron suboxide. FIG. 4 graphically shows the theoretical lapping According to the invention, the novel form of boron 45 performance on silicon carbide of the BxO, diamond, suboxide is produced by reacting stoichiometric and boron carbide, as a function of their Knoop hard amounts of elemental boron and boron oxide in accor nesses (KHN100). dance with the chemical equation: FIG.5 graphically shows the actual lapping results of 16B-B2O3-3B6O (3) BxO, diamond, and boron carbide, lapping silicon car 50 bide. under carefully controlled conditions. The reaction is FIG. 6 graphically shows the theoretical lapping carried out in a specially designed cell at a temperature performance on glass of the BxO, diamond, and boron of about 1900 C. to about 2100 C., and at a pressure in carbide, as a function of their Knoop hardnesses the range of about 3,000 to about 4,000 psi, for a suffi (KHN100). cient time to produce a form of boron suboxide which is 55 FIG.7 graphically shows the actual lapping results of at least 95% by weight B6O and has an average the BxO, diamond, and boron carbide, lapping glass. KHN100 hardness value of at least about 3800 kg/mm2. FIG. 8 is a photomicrograph of a sample of the new Furthermore, while the B2O3 starting material in the superhard form of boron suboxide made with magne above chemical equation is assumed to be essentially sium sintering aid at a magnification of 1330X. pure (e.g., about 99.9% pure), surprisingly it has been FIG. 9 is a plot of the X-ray diffraction pattern ob found that if the elemental boron used as a starting tained with copper K-alpha radiation of the sample material is less than about 95% pure a B6O material shown in FIG. 8. which is harder than previously reported in the litera FIG. 10 is a photomicrograph of another sample of ture can be formed. It was found that the impure B the new superhard form of boron suboxide at a magnifi contained about 6% Mg. It is believed that the Mg aids 65 cation of 1330X. the sintering of the boron suboxide, so that an improved FIG. 11 is a plot of the X-ray diffraction pattern form of B6O is produced which has greater hardness. obtained with copper K-alpha radiation of the sample The quantity of boron used is that suggested by equa shown in FIG. 10. 5,366,526 7 8 FIG. 12 is a plot of average hardness (KHN) values The preceding examples of methods, however, are only for a variety of materials including the new superhard given by way of illustration and not by way of limita form of boron suboxide. tion. FIG. 13 is a photomicrograph at a magnification of The preferred method of producing the boron subox 1330X of a comparison sample of boron suboxide which 5 ide (BxO) composition is by hot-pressing. Further, the is not superhard and was made using high purity boron hot-pressed boron suboxide (BxO) composition is more (99.9% B) mixed with boron oxide to B6O stoichiome preferably made according to the following process. try. Excess boron was not added in this case to compen The novel boron suboxide material of the present inven sate for the surface boron oxide layer on boron, nor was tion is made by hot pressing a stoichiometric mixture of a sintering aid used. O elemental boron and boron oxide powders in a specially FIG. 14 is a plot of the X-ray diffraction pattern designed cell. Preferably, both the boron oxide (B2O3) obtained with copper K-alpha radiation of the compari powder and the elemental boron powder are of high son sample shown in FIG. 13. purity (e.g., 99.9% pure). FIG. 15 is an unetched photomicrograph at a magni The boron and boron oxide powders are mixed to fication of 1330X of a fine grain form of the new super 15 gether in stoichiometric proportions according to equa hard boron suboxide. tion (3). It is important that the two powders be mixed FIG. 16 is an etched photomicrograph at a magnifica and milled very thoroughly to break up agglomerates tion of 1000X of large grain boron suboxide. and/or reduce the size of the larger particles. This may FIG. 17 is an etched photomicrograph at a magnifica be accomplished for example by placing the mixture in tion of 4500X of fine grain boron suboxide. a container with tungsten carbide balls or any other FIG. 18 is a plot of the X-ray diffraction pattern suitable media as a mixing aid and hexane or other non obtained with copper K-alpha radiation of fine grain oxygenated dispersion liquid (; by volume) and tum boron suboxide. bling for at least 8 hours to ensure intimate mixing and allow reduction in powder particle size or agglomer DETAILED DESCRIPTION OF THE 25 ates. An alternate mixing method would be an attrition INVENTION milling technique or any other mixing technique to The method of removing material from a surface achieve the same blend in a shorter time. This slurry comprising the step of abrading a surface with an abra should be dried to evaporate any remaining hexane sive tool or powder comprising a boron suboxide (BXO) without altering material composition. This is followed abrasive mixture wherein during the abrading step deg 30 by screening to reduce large agglomerates. radation of the boron suboxide (BxO) abrasive composi A mixture of boron and boron oxide powders pre tion is minimized can be achieved by processes which pared in this manner can be converted into the novel are known in the art. These processes or methods of boron suboxide material by hot pressing the mixture at abrading a surface include for example loose abrasive temperatures in the range of about 1800-2200 C. and lapping and polishing; fixed-abrasive lapping and pol 35 at pressures of about 2,000-6,000 psi while encapsulated ishing; honing and superfinishing; wire sawing; abrasive by hexagonal boron nitride or another suitable barrier flow machining; ultrasonic machining; abrasive jet ma material, such as tantalum. For this purpose, the spe chining; abrasive waterjet machining; low temperature cially designed cell shown in FIG. 1 may be used. The coated abrasive grinding and low temperature bonded cell comprises a graphite mold having outer wall 12 and abrasive grinding. These processes will be described inner wall 14. A cylinder 16 made from hexagonal later and can be run at low temperatures which allows boron nitride forms a part of the inner wall 14. The for superior abrading results with boron suboxide boron/boron oxide mixture 18 is positioned in the (BxO). The examples are, however, given by way of graphite mold within the hexagonal boron nitride cylin illustration and not by way of limitation. der. The boron/boron oxide mixture is then sandwiched Boron normally has a valence of 3 and reacts with 45 between hexagonal boron nitride plates 21,22. The hex oxygen to form boron oxide having the stoichiometric agonal boron nitride plates 21,22 are set between layers formula B2O3. Under suitable conditions, boron may 25,26 of hexagonal boron nitride powder. Another mass react with oxygen and form compounds in which boron of hexagonal boron nitride powder 24 is confined be exhibits a valence less than 3. These conditions may tween a second set of boron nitride plates 20,28. Graph include variations in temperature and pressure as well as 50 ite pistons 32,34 press against the hexagonal boron ni other processing conditions known in the art. For pur tride powder 25 and the hexagonal boron nitride plate poses of this application, the term “boron suboxide' is 28 thereby compressing the boron/boron oxide mixture defined as boron/oxygen binary compounds wherein while encapsulated with hexagonal boron nitride or boron has a valence less than 3. Since different varieties other suitable barrier. of boron suboxide have been reported by others, boron 55 When the components are assembled and loaded with suboxide will be generally designated with the chemical premixed powders as described above and subjected to formula (BxO). pressures of about 2,000 to about 6,000 psi and tempera The boron suboxide (BxO) composition used in the tures of about 1500 C. to about 2200 C. for periods of boron suboxide (BxO) abrasive mixture of the present about 5 minutes to 3 hours, the novel boron suboxide invention can be produced by hot-pressing, hot isostatic 60 material is formed. For example, a 30 gram sample of pressing, metal oxide derivation, boric acid derivation, stoichiometric boron (90-92% pure boron)/boron oxide chemical vapor deposition, sol-gel derivation, plasma is subjected to a pressure of 3,240 psi and a temperature jet derivation and any combinations of these and other of 1960 C. for about 3 hours to form boron suboxide processes known in the art. Each of these methods which is at least about 95% by weight of B6O and has an produce the boron suboxide (BxO) composition in vari 65 average KHN100 hardness value of at least about 3800 ous physical forms which may have to be further pro kg/mm2 and more preferably about 4250 kg/mm2. cessed into a loose boron suboxide (BxO) abrasive pow Since the scatter of average KHN100 values for a der to be used in the abrasive composition or mixture. given material is no more than about 25-50 kg/mm2, 5,366,526 10 and the average KHN100 values of the thus produced ferred hot-pressing method, the coarsely crushed e.g. 18 boron suboxide material is at least about 200 kg/mm2 mesh (U.S. Standard Sieve Series) (approx. 1000 mi and more typically about 650 kg/mm2, greater than any cron) boron suboxide (BxO) material must be subjected previously reported value for a boron suboxide mate to further processing. The coarse boron suboxide (BxO) rial, it is concluded that the material produced in accor composition is preferably processed by being placed in dance with the present invention is a new superhard a mill with grinding media and milled dry for a time form of boron suboxide. X-ray diffraction, electron period sufficient to shape and comminute the material. microprobe analysis and transmission electron micros The powder is monitored for particle size distribution copy confirm that this new superhard form of boron by way of image analysis as well as microscopic inspec suboxide comprises at least about 95% by weight of 10 tion before milling and during the milling process. The polycrystalline B6O and has a more perfect crystal resulting comminuted fine powder is screened through structure with fewer defects than softer forms of boron a 3 mesh screen (U.S. Standard Sieve Series) to separate suboxide also examined. This method of producing the stainless steel milling media. The separated boron boron suboxide (BxO) by hot pressing is, however, suboxide (BxO) composition is washed with 13NHCl to given as an illustration and not as a limitation. 15 remove any iron, chromium and nickel contamination Boron suboxide made in this manner and having a which resulted from milling in the stainless steel milling KHN100 hardness of at least about 3800 kg/mm2 is in the equipment. Typically this step is carried out in a poly form of a solid mass when it is removed from the cell. It mer container, with the mixture of boron suboxide can then be crushed into granules and sized by tech (BxO) powder and Hicl solution preferably being stirred niques well known to those skilled in the art. The pow 20 der can be used in low temperature applications as an for 10 or 15 minutes. When no further turbulence oc abrasive grit, or the grit can be bonded to tools which curs then the slurry is heated to about 180' F. (82.2° C.) require highly abrasive surfaces, for example, grinding and maintained at that temperature for several hours; wheels, drill bits, machining tools, etc. Other boron the liquid is removed and the washing step with HCl is suboxides (BxO) which can be produced by the pro 25 repeated to ensure complete removal of all metal con cesses described above with KHN100 hardnesses of less tamination. The purified fine powder is then elutriated than 3800 kg/mm2 are expected to produce superior to separate the material into several fractions having results also in low temperature applications as an abra different particle size ranges, e.g. 5 to 7 microns, 3 to 5 sive grit, or when bonded to tools which require highly microns, and 1 to 3 microns. As mentioned earlier, these abrasive surfaces, for example, grinding wheels, drill 30 are the preferred methods of processing and further bits, machining tools, etc. refining the boron suboxide (BxO). This example is not, The bulk boron suboxide (BxO) which is in the form however, the only method of processing the boron of an ingot or slug and which is crushed into the boron suboxide (BxO) composition, and should be considered suboxide (BxO) powder of the invention has a Knoop as an illustration rather than a limitation. hardness (KHN100) of preferably greater than about 35 The boron suboxide (BxO) composition in loose pow 3000 kg/mm2; still preferably greater than about 3100 der form preferably has an average particle size be kg/mm2; still preferably greater than about 3200 tween from about 0.005 microns to about 500 microns, kg/mm2; still preferably greater than about 3300 more preferably an average particle size between from kg/mm2; still preferably greater than about 3400 about 0.05 microns to about 200 microns, and most kg/mm2; still preferably greater than about 3500 preferably between from about 0.1 microns to about 60 kg/mm2; still preferably greater than about 3600 microns. kg/mm2; more preferably greater than 3700 kg/mm2; The boron suboxide (BxO) composition can be com, and most preferably greater than about 3800 kg/mm2. bined with other abrasives to form abrasive mixtures. The chemical composition of the boron suboxide The abrasive mixture used as a lapping powder may (BxO) produced is preferably at least about 70% by 45 include the boron suboxide composition alone or the weight of boron suboxide and as much as about 30% by boron suboxide (BxO) composition in combination with weight of other materials such as boron, boron rich at least one other abrasive for example such as fused phases, or a sintering aid such as oxides of magnesium, aluminum oxide, seeded aluminum oxide, sintered alu beryllium, calcium, strontium, barium, yttrium or other minum oxide, silicon carbide, boron carbide, silicon Group IIA elements, and more preferably at least about 50 nitride, cubic boron nitride, mono and polycrystalline 95% by weight of boron suboxide (BxO) and as much as diamond, zirconium oxide, metal carbides and the like, about 5% by weight of other materials such as boron, including combinations of one or more of these abrasive boron rich phases, or a sintering aid such as oxides of materials with the boron suboxide. In addition, other magnesium, beryllium, calcium, strontium, barium, yt grindings aids can be added such as lubricants. The trium or other Group IIA elements. 55 boron suboxide (BxO) composition preferably forms The comminuted granules or particles of the boron from about 5 to about 100 wt % of the boron suboxide suboxide (BxO) composition are each made up of a (BxO) abrasive mixture, preferably from about 10 to number of very fine grains or crystallites ranging in size about 90 wt % of the abrasive mixture, more preferably preferably from about 0.001 microns to about 150 mi from about 20 to about 80 wt % of the abrasive mixture, crons, more preferably from about 0.01 microns to and most preferably from about 20 to about 60 wt % of about 60 microns, and most preferably from about 0.05 the abrasive mixture. These abrasive mixtures can be microns to about 40 microns. If the granules or particles used in forming an abrasive tool or in loose abrasive of the basic boron suboxide (BxO) composition are powder applications. comminuted to for example particles 40 microns or The surface which is abraded is for example a metal, smaller then obviously each particle may be made up of 65 glass, ceramic, polymer, wood or any combination of a single grain or pieces of a single grain. these or other surfaces known to those skilled in the art. Because quality abrading is particle size dependent, These examples are, however, given as an illustration when the boron suboxide (BxO) is made by the pre rather than a limitation. 5,366,526 11 12 The term abrasive tool is meant to define any device tion and not by way of limitation. The barrier coating designed for abrading. Examples of abrasive tools in can be any coating used by those skilled in the art to clude grinding wheels, cutting wheels, coated abrasives, prevent degradation of the boron suboxide (BxO). Ex wire saws, and honing sticks. These examples are, how amples of these barrier coatings include SiC, diamond, ever, given as an illustration rather than a limitation. metal-metal oxide mixtures, metals, Si3N4, and combi The manufacture of some bonded abrasive tools re nations thereof. Further, these examples of barrier coat quire that the abrasive be subjected to high tempera ings are given by way of illustration and not by way of tures in the manufacturing process such as, for example, limitation. the manufacture of vitrified bonded grinding wheels. For example, in order to prevent degradation by Further, the use of bonded and coated abrasives at 10 oxidation a barrier coating must be applied which does higher speeds generally increase temperatures during not oxidize the boron suboxide (BxO) through oxygen grinding to well above room temperature, and in the in the coating while further preventing oxidation by case of high speed grinding of metals the contact tem diffusion of oxygen through the barrier coating of the perature between the metal and the abrasive can be at or boron suboxide (BxO) at high temperatures during man near the melting point of the metal. Boron suboxide 15 ufacturing. (BxO), boron suboxide (BxO) compositions and boron Lapping or polishing are two of the processes or suboxide (BxO) mixtures are found to degrade at ele methods of abrading a surface which gives superior vated temperatures. Degradation for the purpose of this results in abrading a surface. There are several methods application is defined as the change in chemical and of lapping which can be used which include but are not physical properties of the boron suboxide. Various fac 20 limited to single-side flat lapping, double-side flat lap tors influence the degradation including the atmosphere ping and cylindrical lapping between flat laps. There surrounding boron suboxide (BxO). Therefore, abrasive also are three common polishing processes known in the articles manufactured with boron suboxide (BxO) must art: mechanical polishing, chemical polishing, electro be manufactured at temperatures below which the polishing and a combination thereof. Materials can be boron suboxide does not degrade or where the degrada 25 either hand lapped or mechanically lapped. tion is minimized or manufactured at higher tempera Lapping and polishing with a boron suboxide (BxO) tures while simultaneously controlling factors such as abrasive composition or mixture in the powder form the atmosphere in order to prevent degradation of the preferably involves the use of equipment comprising a boron suboxide (BxO). Common atmospheres which means for holding and/or guiding the workpiece to be could potentially degrade boron suboxide (BxO) 30 lapped or polished, and at least one lap plate. The loose through oxidation are for example air, O2 and oxygen boron suboxide (BxO) abrasive composition in the pow containing bonds or media at elevated temperatures. der form is made into a slurry with a water, oil, water These examples are, however, given as illustrations and soluble oil, or a combination of organic compounds like not as limitations. ethylene glycol and butyl cellosolve, based liquid vehi The boron suboxide can be used in applications 35 cle, and is continuously or intermittently applied be whereby during the abrading step the boron suboxide tween the workpiece and the lapping plate. Pressure is (BxO) is maintained at a temperature at which degrada applied to the workpiece and lap plate and the latter is tion of the boron suboxide does not take place or is rotated. This technique produces only one precision flat minimized over the life of the abrasive tool or powder. side on a workpiece. When the part or workpiece must By minimized, it is meant that preferably 60% by have two sides in perfect parallelism both sides of the weight of the boron suboxide (BxO) remains in the same workpiece are lapped simultaneously using a more com chemical or physical form, more preferably 75% by plex machine made up of an upper and a lower lap plate, weight of the boron suboxide (BxO) remains in the same and special holders for the workpieces with abrasive chemical or physical form, and most preferably 90% by slurry being fed between the upper lap plate and the weight of the boron suboxide (BxO) remains in the same 45 upper surface of the workpiece, and between the lower chemical or physical form over the life of the abrasive lap plate and the lower surface of the workpiece. The tool or powder. For example, the processes or methods holders for the workpiece are typically sprocket-type ofabrading a surface with boron suboxide (BxO) should carriers which are flat relative to the lower lap and are include methods of abrading which do not oxidize the rotated by a centrally located driving means. Still an boron suboxide (BxO), or where the boron suboxide 50 otherlapping-polishing mode is the lapping or polishing (BxO) oxidizes at a very low rate. While these processes of cylinder shaped workpieces which is usually done may not result in superior abrading results using boron with flat lap plates. suboxide (BxO) under every processing parameter, the While the major component in lapping is the abrasive, superior results will be achieved if the process is ad there generally must be a fluid vehicle, the composition justed to prevent or minimize degradation of the boron 55 of which can have a substantial effect on quality of the suboxide (BxO). To prevent degradation of the boron lapping process. The make-up of the fluid vehicle or suboxide (BxO) in an air atmosphere, preferably means compound vehicle portion of the lapping slurry is dic keeping the temperature of the boron suboxide (BxO) in tated to some degree by the abrasive, the lapping equip the tool or the powder during abrading below 600 C., ment, the lapping conditions, and the material being more preferably below 550 C., and most preferably lapped. There is no universal fluid but most are com below 500 C. posed of a certain group of basic materials. The main The boron suboxide (BxO) composition can be constituent of the fluid is water, water/water soluble coated with a barrier which prevents its degradation oil, oil or polymers in which are dispersed, for example, during the manufacture of abrasive tools with the boron viscosity enhancers, lubricants, wetting agents, anti suboxide (BxO). The barrier coating can be applied by 65 caking agents, anti-foam compounds, and bactericides, various techniques known in the art including, for ex or other micro-organism controlling substances. Fur ample, chemical vapor deposition and physical vapor ther, it should be noted that some vehicles can be used deposition. These examples are given by way of illustra which only become fluid under lapping pressure. The 5,366,526 13 14 abrasive and the fluid vehicle together are called the of 4140 Steel, 88.2% of the amount of 12L14 Steel and lapping slurry. 94.5% of the amount of 390 Aluminum removed by The abrasive mixture which is or includes boron diamond powder over the same lapping area. suboxide (BxO) is added to the fluid in amounts varying In Example 10, the test data clearly shows that the preferably from about 0.1% to about 25% by weight of 5 use of boron suboxide (BxO) is comparable to the use of the entire slurry composition and most preferably from monocrystalline diamond as a lapping abrasive in the about 0.2% to about 10% by weight. As already pointed amount of material removed. Again, the material re out, the precise make-up of the lapping slurry with moval was based on the same abrasive concentrations, respect to specific amounts of boron suboxide (BxO), fluid vehicles, slurry application rates and lapping pres specific materials used in the liquid vehicle and these 10 sures per material. The boron suboxide (BxO) surpris relative amounts are basically dependent on the lapping ingly removed 22% more silicon carbide, 40% more conditions, the equipment being used, the material being glass and 74% more 4140 Steel than was removed by lapped, and the desired results, all of which are well diamond powder over the same lapping area. known to those skilled in the art. For example the pre The hardness of the bulk boron suboxide (BxO) ferred fluid used in the lapping slurry for a 310 Stainless 15 (KHN100 3800 kg/mm2) as compared to diamond Steel is composed of 25% polyalkylene glycol and 75% (KHN100 7000 kg/mm2) would predict that the boron ethylene glycol ether by volume. The preferred carrier, suboxide (BxO) would perform only half as well as the however, would change depending on the material diamond in terms of material removal. The excellent being lapped and other lapping conditions. results of Examples 9 and 10 are shown in Tables VI As mentioned earlier, the invention is based on the 20 and VII, and even more dramatically in FIGS. 2 unexpected performance of boron suboxide (BxO) com through 7. FIGS. 2, 4, and 6, show the theoretical position used as an abrasive tool or powder for abrad grinding performances of boron suboxide (BxO) in ing, wherein during abrading the boron suboxide (BxO) grinding 4140 steel, silicon carbide, and glass, respec composition is maintained at low temperatures. Gener tively, based on what the material removal rate of boron ally, one skilled in abrasive technology would expect an 25 suboxide (BxO) should be considering the Knoop hard abrasive grit to perform consistently in relation to other ness KHN100 of the three materials. The predicted theo grits based on mechanical properties, i.e., hardness, in a retical grinding performance of boron suboxide (BxO) variety of applications (e.g., diamond and cubic boron is the expected grinding performance of boron suboxide nitride perform similarly relative to each other in both (BxO) based on its Knoop hardness. The theoretical grinding and lapping applications). Boron suboxide 30 grinding performance is interpolated from a curve relat (BxO) does not, however, behave consistently in this ing the theoretical grinding performance of both boron manner. Example 8 shows that boron suboxide (BxO) carbide and diamond to their relative hardness. In all used in grinding wheel applications was inferior to cases the boron suboxide (BxO) had a predicted theoret seeded aluminum oxide, cubic boron nitride and ical performance somewhat better than that of boron diamond. Table TV shows the results of grinding tests 35 carbide but grossly inferior to the theoretical perfor comparing the grinding performance of boron suboxide mance of the diamond abrasive powder. While the ac (BxO), seeded aluminum oxide and cubic boron nitride tual lapping performance is in reasonable agreement on steel and tungsten carbide where during the abrading with respect to the predicted performance for the boron by grinding the boron suboxide (BxO) reached tempera carbide and the diamond, the predicted versus the ac tures at which the boron suboxide (BxO) oxidized. The tual grinding results with respect to the boron suboxide boron suboxide (BxO) performed inferior to seeded (BxO) was surprising in that the boron suboxide (BxO) aluminum oxide and significantly inferior to cubic had unexpectedly similar results when compared to the boron nitride. Table V shows the results of grinding diamond. These results are surprising in that the boron tests comparing the grinding performance of boron suboxide's (BxO) performance is surprisingly higher suboxide (BxO) with diamond where again during the 45 than the hardness of the three materials would suggest. abrading the boron suboxide (BxO) reached tempera These unexpected results are further supported in Ex tures at which the boron suboxide (BxO) oxidized. The ample 11 where with a preferred carrier the boron sub boron suboxide (BxO) performed significantly inferior oxide (BxO) is capable of stock removal at over 15 times to the diamond. Additionally, boron suboxide (BxO) the rate of monocrystalline diamond. was tested in several saw blade applications. In all tests, 50 Fixed abrasive lapping is another process or method the boron suboxide (BxO) performance was inferior to of abrading a surface which gives superior results in seeded aluminum oxide, cubic boron nitride and abrading a surface. The fixed abrasive lapping is an diamond. The boron suboxide (BxO) provided little to efficient alternative compared to the loose abrasive no cutting action while wearing readily. lapping in obtaining the same desired dimensional accu In contrast, Examples 9 and 10 are comparative tests 55 racy and surface finish. In a fixed abrasive lapping/pol showing the unexpected lapping performance of the ishing operation, the abrasive particles such as boron invention boron suboxide (BxO) as compared to boron suboxide grit are bonded (or embedded) in a bonding carbide and diamond lapping abrasives on various mate matrix with a portion of the abrasive grit protruding rials. In the results shown in Example 9, the boron sub from the matrix. The exposed portion of abrasive grit oxide (BxO) performed surprising well in comparison acts as cutting point against the moving workpiece(s) to with diamond powder. The material removal was based remove material gradually and eventually achieve the on the same abrasive concentrations, fluid vehicles, desired goals. Since the abrasive grit is being held firmly slurry application rates and lapping pressures per mate in this manner, it does not roll away as freely as the rial. The amount of material removed from the surface loose particles. Therefore, it can be used and consumed of the samples being lapped with boron suboxide (BxO) 65 more efficiently than the loose abrasive particles. This was slightly lower, but similar to the amount of material means lower cost per finished part. being removed with diamond powder. The boron sub Low pressure, low speed, and low power operation oxide (BxO) surprisingly removed 75% of the amount conditions reduce the likelihood of increased tempera 5,366,526 15 16 tures which can lead to the oxidation of the boron sub Abrasive flow machining is another process or oxide (BxO) in fixed abrasive lapping. Thus leading to method of abrading a surface which gives superior superior results using boron suboxide compared to that results in abrading a surface. The abrasive flow machin of other conventional abrasives, and makings it a far ing (or known as extrusion hone) uses two opposed superior lapping abrasive than conventional abrasives 5 cylinders to extrude semisolid abrasive media back and such as silicon carbide, boron carbide, etc. In addition as forth through the passages formed by the workpiece discussed earlier, the superior performance of boron and the tooling. By repeatedly extruding the media suboxide when compared to diamond in lapping various from one cylinder to the other, an abrasive action is work materials can also be expected in fixed abrasive produced as the media enters the restrictive passage and lapping. 10 travels through or across the workpiece. The machin In a fixed lapping operation, the bond matrix systems ing action is similar to a grinding or lapping operation in for a fixed abrasive product can be either vitreous, that the abrasive media gently polish the surfaces or metal alloys, or a resin/polymers. Care must be taken in edges. manufacturing the fixed abrasive product to prevent The process is abrasive only in the extrusion area, oxidation of the boron suboxide (BxO). In vitreous bond 15 where the flow is restricted. When forced into a re systems, the bonding matrix will contain, but is not stricted passage the polymer carrier in the media tempo limited to, glass, glass softener, filler, and/or pore indu rarily increases in viscosity; this holds the abrasive cers. In metal bond systems, the bonding matrix con grains rigidly in place. They abrade the passages only tains, but is not limited to, soft metal alloys, particularly when the carrier is in the more viscous state. The vis copper and/or silver based. In resin/polymer bond 20 cosity returns to normal as the abrasive slurry or media systems, the bonding matrix can be, but is not limited to, exits the restrictive passage. PVA, polyurethane, rubber, resins, vinyl film, mylar Abrasive flow machining can process many inaccessi film, polyester, or other natural and synthetic polymers. ble passages on a workpiece simultaneously, and handle Honing/superfinishing is another process or method multiple parts at the same time. It is used to deburr, of abrading a surface which gives superior results in 25 polish, or impart a radius upon surfaces or edges. abrading a surface with boron suboxide (BxO) or com The abrasive media consist of a pliable polymer car binations of (BXO) and other abrasives. Honing/super rier and a concentration of abrasive grains. The carrier finishing is a controlled, low-speed sizing and surface is a mixture of a rubberlike polymer and a lubricating finishing process in which stock is removed by the fluid. By varying the ratio of the two components, the shearing action of the bonded abrasive grit of a honing 30 viscosity of carrier can be modified continuously. Abra stone, or stick. During honing/superfinishing the oxida sive grains are either boron suboxide (BxO) alone or a tion of boron suboxide (BxO) can be minimized or con mixture of boron suboxide (BxO) and other abrasive trolled. materials such as silicon carbide, aluminum oxide, or Honing machines apply either one or several sticks boron carbide, etc. The typical abrasive particle size mounted on the periphery of a cylindrical body to the 35 range is 10 microns and finer. The superior hardness of work surface. During operation, the stone(s) have a boron suboxide will greatly enhance the workpiece simultaneous rotating and reciprocating action to re material removal rate and increases the range of work move work material thus achieving desired dimensional piece materials that can be machined by this process. accuracy and surface finishing characteristics. Ultrasonic machining is another process or method of The honing stones (also known as honing sticks) may 40 abrading a surface which gives superior results in abrad consist of particles of boron suboxide (either alone or ing a surface with boron suboxide (BxO). Ultrasonic mixed with other abrasive grits) bonded together by machining is a process that utilizes ultrasonic (approx. vitreous glass, resinoid, or metal. The particle size of 20 Khz) vibration of a tool in machining of hard, brittle, abrasive grit is typically 500 microns or finer with an nonmetallic materials. This process consists of two abrasive concentration ranging from 10% to 80% by 45 methods: 1) ultrasonic impact grinding, and 2) rotary volume. The glass bond systems contain mostly silica ultrasonic machining. along with various glass softener(s) and/or other fil In ultrasonic impact grinding, an abrasive slurry ler(s). The resinold bond systems can be any natural or flows through a gap between the workpiece and the synthetic resins or polymers. The typical metal bond vibrating tool. Material removal occurs when the abra systems contain soft metal alloys such as, but are not 50 sive particles, suspended in the slurry, are struck on the limited to, copper based or silver based alloys. downstroke of the vibrating tool. The velocity imparted Wire sawing is another process or method of abrad to the abrasive particles causes microchipping and ero ing a surface which gives superior results in abrading a sion as the particles impinge on the workpiece. The surface with boron suboxide (BxO). Wire sawing is a process forms a cavity in the shape of the tool. The cutting/slicing process used in slicing thin wafers out of 55 abrasive slurry typically consists of approximately 50% a bulk material. Wire may be pulled through a reservoir water and 50% abrasive particles by volume. The abra containing abrasive slurry where the abrasive particles sive is either purely boron suboxide (BxO) or a mixture form a coating on the wire. When the wire passes of boron suboxide (BxO) and other abrasive materials. through the work materials, the abrasive particles The typical particle size is 75 microns or finer. abrade the workpiece and cut through it. This is a con The rotary ultrasonic machining is similar to the tinuous process in which particle pick up and cutting conventional drilling of glass and ceramic with take place simultaneously. diamond core drills, except that the rotating core drill is Under this cutting mechanism, the greater the differ vibrated at an ultrasonic frequency of 20 Khz or so. The ence in relative hardness between abrasive and work tools are made by plating or brazing abrasive particles material, the faster the cut rate will be. Therefore, the 65 of boron suboxide to a tool form. As the tool contacts boron suboxide (BxO) will offer superior performance and cuts the workpiece, a liquid coolant, usually water, in this application compared to silicon carbide and is forced through the bore of the tube to cool and flush boron carbide. away the removed material. 5,366,526 17 18 One advantage of using boron suboxide (BxO) in this microscope at a magnification of 1330X. FIG. 8 is a process is that the superior hardness of boron suboxide reproduction of the image seen through the microscope. will greatly enhance the workpiece material removal It shows light gray areas containing primarily B6O and rate, as compared to the silicon carbide, boron carbide, less than 5% Mg and W, dark gray areas containing and aluminum oxide. This superior hardness also in approximately 10% B, 55% O and 35% Mg, and white creases the useful range of workpiece materials that can areas containing approximately 95-96% B, 1-2% W, be machined by this process. and 2-3% Mg. Abrasive water jet machining is another process or A sample of NM086 was also subjected to X-ray method of abrading a surface which gives superior diffraction analysis. FIG. 9 shows the results that were results in abrading a surface with boron suboxide (BxO). 10 Abrasive jet machining is a process that removes mate obtained. The sharpness and position of the peaks dem rial from a workpiece through the use of abrasive parti onstrates that the NM086 sample consisted of a crystal cles entrained in a high velocity gas stream. This pro line product with lattice constants of a=5.384 cess removes material by the impingement of abrasive 35A-0.00051A and c=12.3175A-0.0062A when in particles on the work surface. It differs from conven dexed as a hexagonal unit cell. Transmission election tional sandblasting by using smaller-diameter abrasives microscopy (TEM) photographs and electron diffrac and a more finely controlled delivery system. It is typi tion patterns of the NM086 confirmed the presence of cally used to cut, clean, peen, deburr, deflash, or etch fewer faults in this sample than found in softer samples glass, ceramics, stones, or hard metals. The abrasive can of B6O. be boron suboxide (BxO) particles alone or a mixture of 20 It was concluded that NM086 was a new superhard boron suboxide (BxO) and other abrasive material(s). form of boron suboxide which was much harder than Grit size is typically 75 microns or smaller. Boron sub any previously known form of boron suboxide, and oxide's superior hardness, compared to any other abra which consisted primarily of polycrystalline B60 with sive used in the field, will improve productivity through relatively few defects or dislocations in the material. enhanced material removal rate. Abrasive jet machining is another process or method 25 EXAMPLE 2 of abrading a surface which gives superior results in The conditions of Example 1 were repeated except abrading a surface. Abrasive waterjet machining is a that this time the boron/boron oxide sample weighed process that uses an abrasive waterjet as a cutting tool. 18.5g and was subjected to a temperature of 1960° C. at The incorporation of abrasive particles in waterjet a pressure of 3241 psi for about three hours. The sample stream greatly enhances the range of work materials 30 was given the designation NM138 and was tested as in that can be cut by this process. Superhard boron subox Example 1. ide particles can further enhance the cut rate and make The NM138 sample was tested for hardness with a it capable of cutting even harder materials. Knoop indentor and was found to have an average In order that persons in the art may better understand 35 KHN100 value of about 4250 kg/mm2. The sample was the practice of the present invention, the following also inspected visually under a magnification of 1330X Examples are provided by way of illustration, and not with an optical microscope and a photograph thereof is by way of limitation. Additional background informa shown in FIG. 10. The same microstructure and constit tion known in the art may be found in the references and uents are seen in FIG. 10 as were seen in FIG. 8. The patents cited herein, which are hereby incorporated by NM138 sample was also subjected to X-ray diffraction reference. analysis and the results thereof are shown in FIG. 11. EXAMPLES These tests confirm the conclusions reached in Example 1. EXAMPLE 1. The average Knoop hardness of the NM138 sample A 20 g sample of boron/boron oxide powder was 45 was measured under various loads. FIG. 12 illustrates placed in a container containing tungsten carbide balls the results obtained. Also illustrated are average Knoop and hexane liquid (by volume). The 20 g sample con hardness values that were measured for various other sisted of 14.2 g of elemental boron and 5.8g of boron well-known abrasive materials under the same indenta oxide (B2O3). This roughly corresponds to a boron to tion conditions. FIG. 12 shows that the average KHN oxygen ratio of 6:1. The boron oxide powder was 50 value for the NM138 sample of boron suboxide is higher 99.99% pure, while the boron powder comprised than that of polycrystalline cubic boron nitride at a load 91.03% by weight boron, 5.76% by weight magnesium, of 100 g, and is much higher than the hardness values and 2.81% by weight oxygen, the balance being trace measured for all the other abrasive materials at all loads. other elements. The greater decrease in hardness of this new material at The powder mixture was tumbled overnight, placed 55 400 g load is believed to be due to porosity or other in drying trays, and then baked at about 100 C. to flaws in the test material. produce a dry, thoroughly mixed sample. Twenty grams of this sample was placed in a cell similar to that COMPARATIVE EXAMPLE 1. illustrated in FIG. 1 and was heated at 2000 C. under a In order to compare the results obtained for the new pressure of 3650 psi for about three hours to produce superhard form of boron suboxide with previously the new form of boron suboxide. known forms of boron suboxide, Example 1 was re The boron suboxide material was in solid form as it peated except this time essentially pure (99.9%) elemen was removed from the cell. The boron suboxide pro tal boron powder was mixed with pure boron oxide. In duced in this manner was given the designation NM086. this case, the mixture was subjected to a temperature of The NM086 sample was tested for hardness with a 65 1960" C. and a pressure of 3200 psi for 3 hours. All other Knoop indentor and was found to have an average conditions were the same as in Example 1. The sample KHN100 hardness value of 3790 kg/mm2. The NM086 produced in this manner was given the designation sample was also visually inspected under an optical NM176 and was tested as before. 5,366,526 19 20 The average KHN100 value obtained for the NM176 TABLE III sample was only 1568 kg/mm2. A photograph of the Average sample under a magnification of 1330X is shown in Grinding Peak Power FIG. 13. This photograph shows the presence of con Abrasive (Mesh) Ratio (Watts) siderable porosity. This indicates that the material is not NM086 -100/--230 4.2 360 well sintered. The X-ray diffraction pattern shown in CBN -100/--230 (BZN-I) 284 2465 FIG. 14 confirms that NM176 is not a well crystallized Al2O3 (Norton SG) 227 1704 material as many of the peaks are broad compared with -100/--230 the X-ray diffraction patterns of the NM086 and NM138 samples. This may indicate an incomplete 10 The results from the grinding experiments demon chemical reaction and the presence of intermediate strate that B50 having a KHN100 value of at least about phases. 3800 kg/mm2 can act as an abrasive grit. However, the results of the tests shown in Table 3 are somewhat dis EXAMPLE 3 appointing in comparison to CBN and Al2O3 (Norton In another set of experiments, NM086 samples were 15 SG). More recent experiments have shown that the subjected to a friability test. The NM086 samples were reason B6O was sometimes inferior to CBN and Al2O3 removed from the die, crushed and then sized. The grit (Norton SGTM) is because of oxidation of the B60 at was then subjected to a friability test. The same friabil high temperatures. ity test was conducted on a sample of single crystal CBN and on an Al2O3 grit made from seeded gel. 20 EXAMPLES The NM086 material was found to have desirable In an Al390 turning test a B6O cutting tool insert friability characteristics as shown in Table I. (SNE433) performed similarly to a Si3N4 insert with the TABLE I same geometry. Friability Index (50 seconds) 25 EXAMPLE 6 Size (Mesh) NM086 CBN Al2O3 (Norton SG) In the previous examples, the novel superhard boron -60/--80 13 17 35 suboxide material (e.g., samples NM086 and NM138) -100/-- 120 46 37 62 was prepared from a mixture of essentially pure 99.99% - 120/--140 26 35 27 boron oxide powder and boron powder of relatively 30 low purity (90-92%), the main impurity in the boron The friability index is a measure of toughness and is powder being magnesium which is believed to act as a useful for determining the grit's resistance to fracture sintering aid. The average particle size of the boron during grinding. The values in this table are the percent powder was somewhat less than 5 microns. Further of grit retained on a screen after friability testing. This more, the low purity boron and high purity boron oxide procedure consists of a high frequency, low load impact 35 were mixed in proportions so as to provide a mixture test and is used by manufacturers of diamond grit to containing 6 parts boron to 1 part oxygen. When pro measure the toughness of the grit. Larger values indi cessed as described above, the final product was super cate greater toughness. The data show that the NM086 hard boron suboxide having an average grain size of material has friability characteristics similar to that of 40 18-30 microns, interspersed with a small amount (less the CBN tested (BZN-I from General Electric Co.). than 5%) of magnesium borate, and some free boron. EXAMPLE 4 Through subsequent research it has been found that an improved form of fine grain superhard boron subox In another set of experiments, grit made from NM086 ide can be prepared. This improved form of superhard material was subjected to a grinding test. In a first test, 45 boron suboxide comprises a homogeneous composition the NM086 material was used in making a resin bond of B6O throughout, and has a grain size of approxi grinding wheel. mately 1 to 3 microns. This fine grain form of superhard Wet grinding of a D-2 steel workpiece was con boron suboxide was prepared by mixing as described ducted at a traverse speed of 600 in/min and a cross feed of 0.05 inches. The results for the NM086 material earlier high purity (99.9%) boron oxide with high pu 50 rity (99.9%) boron powder having an average particle and for the Al2O3(Norton SG) are shown in Table II. size of less than 1 micron in a proportion so as to pro TABLE II vide 12 parts boronto 1 part oxygen. The excess boron Depth of Average was needed in order to compensate for a boron oxide Cut Grinding Peak Power layer which formed on the surface of the boron parti Abrasive (Mesh) (Inches) Ratio (Watts) 55 cles. Without the addition of any sintering aid, the mix NMO86-60/-200 0.0003 17.4 800 ture of boron and boron suboxide was then loaded into 18.5 800 the reaction cell illustrated in FIG. 1 and subjected to a Al2O3 (Norton SG) 0.0003 21.7 590 -60/-200 21.2 640 temperature of 2100° C. and a pressure of 3500 psi for 20 NM086-60/-200 0.0005 13.4 1000 minutes. 2.6 1160 FIG. 15 is a typical photomicrograph of the product Al2O3 (Norton SG) 0.0005 24.7 700 prepared in this way. It consists of a fine grain B6O with -60/-200 24.6 660 less than 10% of an unidentified boron-rich base. The KHN100 hardness values measured for the fine grain A similar vitreous bond grinding wheel test was con boron suboxide ranged from 3853 kg/mm2 to 4288 ducted using another sample of NM086 material. In this 65 kg/mm2. case, the workpiece was 52100 steel and the infeed was FIGS. 16 and 17 show the difference in grain size 0.001 inches/second. The results are shown in Table III. between the large grain and the fine grain boron subox ide materials. The large grain boron suboxide shown in 5,366,526 21 22 FIG. 16 has an average grain size of approximately 18-30- microns, while the fine grain boron suboxide -continued shown in FIG. 17 has an average grain size of approxi Method of Test: mately 1-5 microns. Wheel Speed: 5000s.fp.m. FIG. 18 shows an X-ray diffraction pattern for the Table Traverse: 600 i.p.m. fine grain boron suboxide. Differences in the X-ray Unit Crossfeed: 50 mils diffraction patterns may also be observed. The D3 Steel had a hardness of Rc 60-63, and the EXAMPLE 7 4340 Steel had a hardness of Rc58-60. The coolant used An experimental design was also conducted wherein 10 was a Master chemical trim VHPE300 G5% ratio with the factors pressure, temperature, boronto oxygen ratio city water for steel grinding, and W&B E55 G2.5% and purity of boron powder were examined to deter ratio with city water for carbide grinding. mine their effects on hardness. Pressure was found to TABLE IV affect hardness the least, i.e., hard materials could be produced over a range of pressures. As a result of this 15 G-ratio % G Power % P finding, it is postulated that it may also be possible to 4340 Steel Seeded A1203 90 100 220 100 produce B6O materials with hardness greater than BO 12 13 520 236 KHN100=3800 kg/mm2 with other apparatuses which D3 Steel are capable of operating at pressures greater than 6000 Seeded A1203 16 100 610 100 psi (for example pressures up to 50,000 psi which are 20 BxO 9 56 860 14 typical of hot isostatic pressing.) CBN 460 2875 380 62 Up to now, all of the methods described for produc Tungsten Carbide ing superhard boron suboxide involved hot pressing of Seeded A203 0.39 100 900 00 boron and boron oxide powders along an axial direction BxO 0.27 69 1800 82 in a cell such as that shown in FIG. 1. It has also been 25 discovered that superhard boron suboxide can be pro A comparative grinding wheel test was performed duced in a hot isostatic pressing process similar to that with boron suboxide (BxO) and diamond as the abrasive described in U.S. Pat. No. 4,446,100 (Adlerborn et al.) on tungsten carbide. As boron suboxide (BxO) has some According to this process, a mixture of substantially reactivity with iron, it was postulated that such reactiv pure boron (99.9%) and boron oxide (99.9%) in a stoi 30 ity would not reduce the performance of boron subox chiometric ratio of 12 parts boron to 1 part oxygen as ide (BxO) on non-ferrous materials. The boron suboxide described in connection with Example 5 was first cold (BxO) and diamond used were both 100/120 mesh at isostatic pressed to form a green body product. The 100 concentration. green body product was then coated with a 2-3 mm boron nitride layer (containing BN, alcohol, and or 35 ganic binder). Subsequent layers 2-3 mm thick of com Test Conditions: Machine: Norton S-3 or B & SSurface Grinder bined boron nitride and silicon carbide, boron nitride, Wheel Speed: 5000 s.lfp.m. and combined boron nitride and silicon carbide were Table Traverse: 600 i.p.m. also applied. The sample was then encapsulated in glass Unit Downfeed: 0.5 mils and subjected to hot isostatic pressing as described in Total Downfeed: 50 mills U.S. Pat. No. 4,446,100. The hot isostatic pressing was Coolant: W & B E55 G 1:40 or equivalent performed at a temperature of 1950 C. and a pressure of 30,000 psi for 30 minutes. The tests were discontinued after the initial pre-grind Fine grain boron suboxide having an average Knoop because the boron suboxide (BxO) wheel wear was hardness KHN100 of 3804 kg/mm2 was produced by this 45 extraordinarily high, see Table V. method. The fine grain boron suboxide produced by this method closely resembled the fine grain boron TABLE V suboxide produced by the hot pressing method de Abrasive Wheel Wear Material Removed Peak Power scribed in Example 6. However, the boron suboxide Diamond 3.6 mills 48.4 mils 760 watts made by hot isostatic pressing was comprised of grains 50 BxO 97.7 mills 0.7 mills 440 watts ranging from approximately 0.1 to 0.5 microns which is substantially smaller than the average grain size of the hot pressed material. EXAMPLE 9 Two lapping slurries were prepared, one with boron EXAMPLE 8 55 suboxide (BxO) of the invention, and a second using The grinding performance of 220 gritboron suboxide GE300 diamond abrasive powder from the General (BxO) at 200 concentration was compared to seeded Electric Company; the diamond abrasive powder hav Al2O3 and CBN (same size and concentration) on D3 ing a particle size range of about 2 to 5 microns, and the Steel. Because the performance was greatly inferior to boron suboxide (BxO) having a particle size range of 1 CBN, the boron suboxide (BxO) was only compared to to 10 microns. The abrasive concentration in the two seeded Al2O3 on 4340 Steel and tungsten carbide work slurries was a standard concentration of 10 carats (2 materials. On all three materials the unit downfeed was grams) per 100 ml of slurry. The fluid vehicle in of the 0.5 mils for a material removal rate of 0.080 in/min/in. two slurries was 80% by weight of ethylene glycol and 20% by weight of butyl cellosolve. The slurries had a 65 viscosity of 40 centipoise as measured using a Brook field Viscosimeter using spindle No. 21. Method of Test: The materials lapped with each slurry were 12L14 Machine: Brown and Sharpe Surface Grinder steel, 4140 steel, and aluminum. The lapping was with a 5,366,526 23 24 Lapmaster 12 machine manufactured by Crane Manu and 75% by volume of ethylene glycol ether. The con facturing Company and using a hardened steel lapping centration of abrasive in the slurry was (24 carats) 4.8 plate rotating at 60 rpm. The abrasive slurry was sup grams of boron suboxide (BxO) composition or mono plied to the lapping plate with a peristaltic pump at a crystalline diamond per 500 ml of carrier. The viscosity rate of 0.7 ml per minute. All the materials were sub of all the slurries tested was the same. The boron subox jected to lapping with each abrasive for a period of 8 hours with a total area lapped per rm of 18.65 in ide (BxO) abrasive and the monocrystalline diamond (0.0121 m). The lapping pressures were 2.83 psi used had a particle size of 3-5 microns. The results are (19.5x103 Pa) on 4140 steel, 21.5 psi (18.8x103Pa) on listed in Table VII. the 12L14 material, and 1.28 psi (8.8x10 Pa) on the 10 TABLE VII aluminum. The lapping pressure was different for each Values material but the same for all three abrasives on a given BxO Diamond BxO Diamond material. The results are shown in Table V. Pressure 6 6 1 1 TABLE VI (psi) 15 Results Material Removal (mg/cm) Surface Roughness 1.66 43 180 155 1214 Steel 4140 Steel 390 Aluminum (micro inch) Diamond 2161.5 1982.6 1789.1 Surf. Rough. (Max) 8.59 7.48 9.42 7.77 Boron Suboxide 1905.9 1489.7 1690.5 (micro inch) Stock Removal 3,239 273 1571 99 20 (mg/inch2) The invention boron suboxide (BxO) lapping powder Stock Removal 11.85 15.82 removes less material for a given amount of abrasive Ratio than does the diamond abrasive. However, as explained above, the boron suboxide (BxO) performs similarly to the diamond despite the broad differential in hardness. 25 EXAMPLE 12 EXAMPLE 10 Boron suboxide (BxO) is used to make a fixed abra Three lapping slurries were prepared, one with boron sive by the following techniques. suboxide (BxO) of the invention, a second using GE300 a) The boron suboxide, or a mixture of boron subox diamond abrasive powder from the General Electric ide and other abrasive(s), e.g. SiC, is blended with poly Company, and a third incorporating boron carbide as 30 vinyl alcohol, foamed, then cured to hard cellular the abrasive; they all had a particle size range of about block. This abrasive pad is used in lapping aluminum 2 to 5 microns. The abrasive concentration in all three disc, silicon disc, etc. The abrasive content of this prod slurries was a standard concentration of 10 carats (2 uct is varied from 5% to 75% by volume. The abrasive grams) per 100 ml of slurry. The fluid vehicle in all grit size is typically 150 microns or finer. Another ex three slurries was 80% by weight of ethylene glycol and 35 ample of this type is a mixture of said abrasive and 20% by weight of butyl cellosolve. The slurries had a polyurethane bonding material. viscosity of 40 centipoise as measured using a Brook b) Boron suboxide, either alone or mixed with other field Viscosimeter using spindle No. 21. a abrasive grain, is either orderly or randomly placed on The materials lapped with each slurry were 4140 top of a flexible substrate film which contains bonding steel, silicon carbide, and glass. The lapping was with a resin(s) or polymer(s). After curing, the abrasive is per Lapmaster 12 machine manufactured by Crane Manu manently held on the substrate. The coated substrate is facturing Company and using a hardened steel lapping cut into various shapes, such as disc, strip, belt, etc., plate rotating at 60 rpm. The abrasive slurry was sup suitable for any desired lapping/polishing applications. plied to the lapping plate with a peristaltic pump at a The typical size of abrasive grit is 850 microns or finer. rate of 0.7 ml per minute. All the materials were sub 45 c) Boron suboxide, either alone or mixed with other jected to lapping with each abrasive for a period of 8 abrasive grain, is mixed with a copper based alloy to an hours. The lapping pressure was different for each ma abrasive concentration ranging from 5% to 75% by terial but the same for all three abrasives on a given volume. The typical size of abrasive grit is 500 microns material. On the 4140 steel the pressure was 2.83 psi or finer. The mixture is heated to an elevated tempera (19.5 x 103 Pa) on the silicon carbide 1.28 psi (8.8x103 50 ture to form a solid segment, plate, or wheel. This plate Pa), and 2.15 psi (14.8x10 Pa) for the glass. The results may or may not have a backing core. This metal bonded were as follows: product can be fitted to lappers or polishing machines to TABLE VII finish various work materials, such as metals, ceramics, Material Removal (mg/cm') 55 glass, stones, etc. 4140 SC Glass d) Similar to c), but the bond system contains mostly Diamond 90.2 72.2 418.8 glass. Boron Carbide 0.4 32.9 301.8 It is understood that various other modifications will Boron suboxide 56.7 88.4 590.3 be apparent to and can be readily made by those skilled 60 in the art without departing from the scope and spirit of the present invention. Accordingly, it is not intended EXAMPLE 1. that the scope of the claims appended hereto be limited Boron suboxide (BxO) was tested with fluids to deter to the description set forth above but rather that the mine the preferred carrier for use with boron suboxide claims be construed as encompassing all of the features (BxO) compositions and mixtures, and to compare the 65 of patentable novelty which reside in the present inven results with the use of these carriers with monocrystal tion, including all features which would be treated as line diamond. The preferred fluid for use with 310 S equivalents thereof by those skilled in the art to which Steel contained 25% by volume polyalkylene glycol the invention pertains. 5,366,526 25 26 What is claimed is: 10. A method of removing material from a surface 1. A method of removing material from a surface comprising the step of: comprising the step of: abrading a surface with an abrasive tool comprising a abrading a surface with an abrasive powder compris boron suboxide (BxO) composition, wherein dur ing a boron suboxide (BxO) composition, wherein 5 ing the abrading step at least 60% by weight of the during the abrading step at least 60% by weight of boron suboxide (BxO) in the boron suboxide (BxO) the boron suboxide (BxO) in the boron suboxide composition does not degrade. (BxO) composition does not degrade. 11. The method in claim 10, wherein the boron subox 2. The method in claim 1, wherein the boron suboxide ide (BxO) composition has a KHN100 of greater than (BxO) composition has a KHN100 of greater than 3800 10 3800 kg/mm2. kg/mm2. 12. The method in claim 10, wherein the powder of 3. The method in claim 1, wherein the powder of boron suboxide (BxO) composition has an average par boron suboxide (BxO) composition has an average par ticle size between from about 0.005 microns to about ticle size between from about 0.005 microns to about 500 microns and wherein the individual particles are 500 microns and wherein the individual particles are 15 made up of grains finer than about 150 microns. made up of grains finer than about 150 microns. 13. The method in claim 10, wherein said boron sub 4. The method in claim 1 wherein said boron subox oxide (BxO) composition comprises at least about 70% ide (BxO) composition comprises at least about 70% by by weight of boron suboxide (BxO). weight of boron suboxide (BxO). 14. The method in claim 11, wherein the boron subox 5. The method in claim 2, wherein the boron suboxide 20 ide (BxO) composition includes up to about 30% by (BxO) composition includes up to about 30% by weight weight of a material selected from the group consisting of a material selected from the group consisting of ber of beryllium, magnesium, calcium, strontium, barium, yllium, magnesium, calcium, strontium, barium, yt yttrium, and mixtures thereof present in said boron trium, and mixtures thereof present in said boron oxide oxide as the element or in the form of a compound of as the element or in the form of a compound of said 25 said elements. elements. 15. The method in claim 10, wherein the boron subox 6. The method in claim 1, wherein the boron suboxide ide (BxO) composition is a boron suboxide (BxO) abra (BxO) composition is a boron suboxide (BxO) abrasive sive mixture with at least one additional abrasive. mixture with at least one additional abrasive. 16. The method in claim 15, wherein the additional 7. The method in claim 5, wherein the additional 30 abrasive is selected from the group consisting of fused abrasive is selected from the group consisting of fused aluminum oxide, seeded aluminum oxide, sintered alu aluminum oxide, seeded aluminum oxide, sintered alu minum oxide, silicon carbide, boron carbide, silicon minum oxide, silicon carbide, boron carbide, silicon nitride, cubic boron nitride, mono and polycrystalline nitride, cubic boron nitride, mono and polycrystalline diamond, zirconium oxide, metal carbides and mixtures diamond, zirconium oxide, metal carbides and mixtures 35 thereof. thereof. 17. The method in claim 10, wherein during the 8. The method in claim 1, wherein during the abrad abrading step at least 75% by weight of the boron sub ing step at least 75% by weight of the boron suboxide oxide (BxO) in the boron suboxide composition does not (BxO) in the boron suboxide composition does not de degrade. grade. 40 18. The method in claim 17, wherein during the 9. The method in claim 8, wherein during the abrad abrading step at least 90% by weight of the boron sub ing step at least 90% by weight of the boron suboxide oxide (BxO) in the boron suboxide composition does not (BxO) in the boron suboxide composition does not de degrade. grade. k : k k 45

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