United States Patent [19] [111 3,903,585 Kosteruk et al. [45] Sept. 9, 1975

[54] METHOD OF BRAZING 2.9791313 4/l96l Steinberg ...... 29/504 X [761 ‘""emors: vakmi" pe‘mvkh Kosm'uki “msa 520918063 44 [3119231 19 gdulerifeurreta] e . . . .al...... v . e . ...t 23:28: i M- Krlvonosa, 19» kv- 5;_Mikhail 3,442,006 5/l969 Grucket et a1...‘ 29/4711 x Savvich Kovalchenko. ulltsa 3,594,895 7/1971 Hill ...... 29/504 x Kapitanovskaya, l0, kv. 20, both of 3,736,648 6/1973 Spielberg ...... t. 29/4731 Kiev, U.S.S.R. [22] Filed: Ann 27, 1972 Primary Examiner—Francis S. Husar Assistant Examiner—Ronald J. Shore [2]] APPL N03 248,295 Attorney, Agent, or Firm—Waters, Schwartz & Nissen Related U.S. Application Data [63] Continuation of Ser. No. 875,503, Nov. l0, i969, [57] ABSTRACT abandoned‘ lnfusible metal alloys are employed both as a parts I ‘ material and as a brazing spelter for the connection of [52] U.S. Cl...... 75/134 V, 2222880122623, various parts and componems made of materialsrbascd [5 H I ‘ C‘ ‘ 823k suoz upon infusible metals and compounds, ceramics. [58 F’: ‘Id """" 473 1 graphite and the like. The alloys are based upon haf ] e o arc "" " ' ‘29/4729’ 477i 7’ nium to which is added some elements selected from ‘ ' ' the subgroup B of the ?rst group of the periodic sys tem and some elements featuring melting points lying [56] References Cited above 600°C and selected from the third to eighth UNITED STATES PATENTS groups of the periodic system. 2,739,375 3/l956 Coxe ...... t 29/473.l X 2,857,663 |0/19ss Beggs ...... 29/504 x 5 Clainw N0 Drawings 3,903,585 1 2 METHOD OF BRAZING nitride, silicon nitride, silicon carbide and many others, This application is a continuation application of ap are not solderable with the use of available conven plication Ser. No. 875,503, ?led Nov. 10, i969 now tional brazing spelters. abandoned. Even in cases where the brazing of high-melting ma The present invention relates to infusible metal alloys terials is rendered practicable, e.g. when connecting employed as a material for various parts and compo graphite with high-melting metals by using a spelter nents and as a brazing spelter to connect various parts with a melting point between lOOO° to l500°C, each made of materials based on high-melting metals and particular brazing spelter possesses its own melting metal alloys, ceramics, graphite and the like. point which is a strictly ?xed constant value. Thus, Use of the herein-disclosed alloy as a brazing spelter brazing of graphite proceeds at a temperature of from may be made in chemical and electrochemical indus l200° to l300°C, each of the spelters being applicable tries for the connection of parts designed to operate in for only a certain range of materials. For instance, a zir corrodents; in electricsal~engineering, nuclear, aircraft conium-based spelter is applicable to the brazing of a and process industries for reinforcing critical and de?nite pair of materials, say, zirconium and poorly heavy-wear components parts and elements. fusible glass. Known inthe present state of the art are brazing al Additionally, a majority of hitherto-known brazing loys containing mostly silver and copper, bronze, plati compounds have a melting point lying not above lOOO° num and employed for soldereing or brazing such wide to l300°C, this being due to these incorporating rela ly-used construction materials, mostly metallic, as vari— tively low-melting substances. On this account, the ous grades of steel and metal alloys. 20 pressure of the vapors of some brazing compounds at However, gaining an ever-growing application at highly elevated temperatures (of the order of lOOO°C) present are materials based upon high melting-point ranges within ID’3 to H)‘4 mm Hg. Therefore, the ap compounds such as carbides, borides, nitrides and sili plication of the above-mentioned brazing spelters to cides, possessing special physico-chemical properties. high-vacuum engineering sometimes proves to be im From these materials are usually made critical parts of 25 practicable. ' various machines designed to operate under heavy con It is an object of the present invention to eliminate ditions such as blades of gas turbines therefore a neces the disadvantages discussed above. sity arises for such parts to be mechanically fastened to It is another object of the present invention to pro other parts made from conventional structural materi vide an alloy that is applicable as a material for making als, i.e., from various grades of steel and metal alloys. 30 various parts and components and as a brazing com Additionally, the above reason necessitates the provi pound for connecting various parts and components, sion of both electrical and thermal contacts between which alloy is capable of connecting a wide variety of both types of parts mentioned above. diverse materials based upon infusible compounds both ln current use are a plurality of soldering or brazing with one another and with other infusible metals, ce spelters enabling a partial solving of that problem as far ramics, graphite and like materials and the various as parts made of graphite, titanium, zirconium, tung physico-chemical properties of which can be regulated sten, niobium and their alloys are concerned. Thus, to insure the best working capacity of the material of when soldering thorium~tungsten wire to molybdenum the brazed connection under given conditions. parts in manufacturing cathode-ray tubes, use is made Said object is accomplished due to the face that the of platinum and its alloys with silver and gold as a braz 40 herein-disclosed alloy, according to the invention, is ing compound, the melting point of the latter falling be based upon hafnium to which is added some elements tween l400° and l8()0°C. selected from the subgroup B of the Ist group of the pe There are also known brazing compounds based riodic system within 2 and 30 percent of the total upon zirconium alloyed with vanadium, tungsten, tita weight of the alloy, said elements being taken either nium, beryllium and niobium additives, said com 45 separately or in various combinations with one another pounds being used for braze—jointing zirconium parts within the afore-stated weight percentage, and to which with poorly fusible glasses. the melting point of the is added also some elements selected from the lllrd to compounds lying between l050° and [300°C Vlllth groups of the periodic system, having a melting Palladium-based brazing spelters have a melting point lying above 600°C and taken either separately or point ranging between [000° and l500°C and are uti 50 in various combinations with one another within 2 to lized for braze-eonnection parts and components made 2l percent of the total weight of the alloy. of molybdenum, tungsten, zirconium and some heat The achieving of the above object has made it possi resistant alloys intended to operate under extra-high ble to provide an alloy that is in fact a highly versatile temperature conditions. brazing spelter capable of the connection of compo To provide a brazed-connection of graphite compo 55 nents made of the most diverse high-melting materials, nents with those made of titanium and zirconium and having a melting point regulatable within a wide tem their alloys, use is made currently of suspensions con perature range and possessing the most diverse physi stituted by ?nely comminuted powdery zirconium, tita co-chemical properties. nium, molybdenum or their alloys, and by gasoline~dis Hafnium, which is the base metal of the herein solved polystyrene. The speci?ed brazing conditions 60 proposed alloy, imparts a high adhesive property to the are as follows: melting point between l200° 'and latter with respect to infusible materials, as well as in l300°C, rarefaction l()"‘ to l0“5 mm Hg. To obtain sures a high melting point. high-quality brazed connections of graphitic compo Additives of the elements of the subgroup B of the lst nents with those made of molybdenum, zirconium, tita group of the periodic system taken in a quantity of from nium and niobium. use is made of brazing spelters con 65 2 to 30 weight percent contribute to the regulation of taining Au, Ni, Ti and Mo. the melting point of the herein-disclosed alloy within However, many of the materials based upon high the required limits, whereas some additives of the ele melting compounds such as boron carbonitride, boron ments selected from the lllrd to Vlllth groups of the pe~ 3,903,585 3 4 riodic system taken in an amount of from 2 to 21 rately or in various combinations with one another weight percent are instrumental in regulating the physi~ within the above-speci?ed limits, and some elements co-chemical properties of the alloy concerned herein. having a melting point lying above 600°C and selected To provide the regulation of the melting point of the from the third to eighth groups of the periodic system alloy within the temperature range of from 1000D to 5 within the range of from 2 to 2l percent of the total l200°C, it is advisable that the elements of the sub weight of the alloy, taken either separately or in various group B of the lst group of the periodic system be taken combinations within the afore-stated limits. in an amount of from 20 to 30 percent of the total The element of hafnium, a basal constituent of the weight of the alloy, while the regulation of the melting present alloy, is a chemically active metal thus contrib point of the alloy within the range of from l200° to 10 uting to high adhesivity of the alloy with respect to in 1500°C is attainable by taking the elements of the sub fusible materials, its high melting temperature calling group B of the lst group of the periodic system in a forth the high melting point of the alloy proper. quantity of from 12 to 20 percent of the total alloy To regulate the melting point of the alloy within the weight. required limits, there are added some elements selected Further, the regulation of the alloy melting point with from the subgroup B of the ?rst group of the periodic in the range of from l500° to l800°C can be obtained system, viz. Cu, Ag and Au. by taking the elements of the subgroup B of the lst The more the herein-disclosed compound is alloyed group of the periodic system in an amount of from 8 to with the afore-mentioned elements the lower its melt 12 percent by the alloy weight, whereas for the regulat ing point. ing of the alloy melting point within the limits of from 20 Additionally, copper, silver and gold due to their 1800° to 2 l 00°C the elements of the subgroup B of the being good brazing agents for metals “per se”, add lst group of the periodic system are advantageously much to the adhesivity of the alloy involved. taken in a quantity of from 2 to 8 percent of the total Furthermore, Cu, Ag and Au being highly current alloy weight. conductive metals, their introduction into the alloy in It is due to the above-described composition that the an amount of up to 30 percent of the total weight of the herein-disclosed alloy will ?nd wide application in the alloy results in its resistivity being reduced about three most diverse branches of engineering and industry, e.g., times which is of special importance when using the in electronic for mechanical attachment and electrical alloy for the purpose of electrical connections. connection of components made from infusible materi— Said elements can be taken either separately or in als such as cathodes from lanthanum hexaboride; in 30 any combination with one another within the limits of chemical machinebuilding for attaching refractory lin from 2 to 30 percent of the total weight of the alloy. Al» ing and some other components made of infusible ma loying of the compound with such an additive has made terials such as linings from silicon nitride; in electrical it possible to regulate the alloy melting point within engineering for attaching and electrically connecting 10000 to 2 l00°C. Thus, should said elements be intro current-conducting elements such as the electrodes in 35 duced within the range of from 20 to 30 percent of the electrolyzers, and for fastening insulators, e.g., those alloy weight, its melting point will be found to lie be made of aluminum oxide. tween l000° and 1200°C, whereas for a percentage of The present alloy is also favorably practicable when alloying ranging between l2 and 20 the melting point utilized in aircraft industry, especially in cases where, will lie between l200° and l500°C. with that percent» in addition to mechanical linkage or attachment, air 40 age ranging from 8 to 122, the melting point will be be tightness is necessary as is the case in making various tween l500° to [800°C and in case of 2 and 8 percent current leads on aircraft. alloying the melting point will range between 1800° and In processing industries the present alloy can ?nd 2 100°C. particular utility when employed for attaching various Introduction of such an additive taken in the afore carbide-tipped heads of cutting tools, in assembling 45 speci?ed percentage has enabled the melting point of large~sized or intricate-shaped carbide-tipped tools the alloy to be regulated within a wide temperature from smaller components, for attaching refracttory range which fact mades it possible to utilize the alloy as composed lining in various Crushers. mills, etc. Addi a brazing agent for connecting the most diverse infus tionally, the alloy is applicable as a bond for abrasive ible materials. wheels such as diamond ones. The most promising To modify the physico-chemical properties of the sphere of application of the present alloy is the process present alloy in a desired direction so as to provide ing industries, this being concerned with the appear maximum approximation of the alloy properties with ance of cutting tools not of such conventional alloys as those of the materials being connected that are pre those based upon tungsten carbide in combination with dominant one under the given particular conditions, cobalt but of other infusible compounds such as bo one more additive is introduced into the alloy selected rides of certain metals, since for these materials the at from the elements of the third to eighth groups of the tachment methods prove to be but slightly developed. periodic system, said elements having a melting point In the following the present invention will be made lying above 600°C. Thus, to connect the materials clear by virtue of speci?c and preferred embodiments whose thermal coef?cient of expansion badly differs thereof described hereinbelow. 60 from that of the brazing alloy, some additive of Fe, Ni The herein-disclosed alloy intended to be employed and Co in an amount of from 2 to 21 weight percent al as a material for manufacturing various parts and com lows the above coefficient of the alloy to be properly ponents and as a brazing alloy for the connection of regulated. various components and parts based upon infusible To impart more hardness to the alloy, some boron or metals and compounds, contains Hf as a base to which carbon is added. is added some elements of the subgroup B of the ?rst Since some of the elements alloyed as an additive group of the periodic system within a range of from 2 to into the brazing compound have a melting point higher 30 percent by weight of the alloy, taken either sepa than that of the basal constituent of the alloy, such an 3,903,585 5 6 additive results in a higher melting point of the alloy as a whole. This holds true particularly of tungsten. ,, Among the elements of the third to eighth groups of AT= 0-01 _2 (Ti-Toll? the periodic system that are concerned with the modifi— 1:] cation of the physico-chemical properties of the pres- 5 ent alloy are: boron aluminum, scandium, yttrium, lan- Where: thanides, carbon, silicon, germanium, titanium, zirco- AT — temperature variation due to the introduction nium, vanadium, niobium (columbium), tantalum, of additives selected from the elements of the third phosphorus, chromium, molybdenum, tungsten, man- to eighth groups of the periodic system, °C ganese technetium (masurium), rhenium, ruthenium, ‘0 Ti -— melting point of each Of the elements Constitut osmium, cobalt, nickel, rhodium, palladium, iridium ing the additive, °C; and platinum. ji -- weight percentage of each of the elements se The melting point of the alloy is approximately calcu- lected from the third to eighth groups of the peri lable proceeding from the assumption that the follow- OdiC system; ing relationship holds true of the speci?ed weight per-- l5 n —— quantity of elements selected from the third to centage range of from 2 to 30 of the additives selected eighth groups of the periodic system. from the subgroup B of the ?rst group of the periodic With due allowance for the latter formula, the ex system: pression for an approximate calculation of the melting point of the present alloy will assume the following T = T,, + 0.033 (T,- — T,,)a 20 form.

A‘ H T= T,,+().U33a[1§—7},+l).tll E (7';—7l_,)(‘i +().()l F. (T,—T,,)‘ji i=l j=l

where: Accuracy of the alloy melting point calculation by T — alloy melting point to be sought, °C; the above formula is within 1 100°C. Thus, the above T" — melting point of the basal constituent of the al- expression will assume its ?nal form:

loy, viz. hafnium; where: Tl — melting point of the additive selected from the 35 T — alloy melting point to be sought, °C; elements of the subgrouup B of the first group of T,, —— melting point of hafnium, °C; the periodic system; a — total weight percentage of the additive selected a — total amount of the additive in weight percent. from the elements of the subgrop B of the ?rst Should the above additive selected from the elements group of the periodic system; of the subgroup B of the ?rst group of the periodic sys- 40 T2 — melting point of copper, °C; tem comprise not a single but a few elements, the afore- k -— quantity of elements selected from the subgroup stated formula assumes the following form: B of the ?rst group of the periodic system except for copper; k Ci — weight percentage of each of the elements in r= 1;, + (mm [BHHH >2‘ (1‘.-—11.>c— 1;, 45 cluded in the amount “k"; ,: T, —— melting point of each of the elements included in the amount °C; where: n — quantity of elements selected from the third to T2 — melting point of copper. °C; eighth groups of the periodic system; T, — melting point of the rest of the additives se- 50 ji —- weight percentage of each of the elements in lected from the elements of the elements of the cluded in the quantity “n". subgroup B of the ?rst group of the periodic sys tem 0C. EXAMPLE 1. C, — weight percentage of all the other additives se- An alloy employed for brazing titanium carbide with lected from the elements of the subgroup B of the 55 niobium carbide has the following composition: ?rst group of the periodic system except for that of Copper; _ _ Constituents Weight Melting point of alloy 01 — total weight percentage of the additive selected of alloy percentage constituents. ‘T from the elements of the subgroup B of. the ?rst Copper 2 In“ group of the periodic system ln the alloy lnvolved; (*0 Silver 1 9st) k —- quantity. - of elements_ selected from the subgroup ZircuniumTitanium 51 ‘9001800 B of the first group of the perlodlc system for the Hafnium balance 2230 additives into the alloy involved less copper. Variation of the alloy melting point caused by the in troduction of the additive selected from the elements 65 Substituting the above-tabulated numerical values occurring in the third to eighth groups of the periodic into the afore-derived formula one will obtain the melt system and taken in an amount of from 2 to 21 weight ing point of the alloy under consideration: T = 2230 + percent, is expressed through the following formula: 0.033 ' 3 [i083 — 2230 + 0.01 (960-l083 )-l I + 0.0l 3,903,585 7 8 [(1800 — 2230)'5 +( 1900— 2230)'l ]= 20901 100°C. Ni -— 3 percent EXAMPLE 2. Hf — balance (58 percent). A alloy for brazing boron carbonitride with tungsten, EXAMPLE 7. the resulting connection having to operate at tempera Au can be employed as an additive in the same cases tures of up to l900°C. The alloy features a minimum as Cu or Ag. However, on account of the high cost of amount of the additive selected from the elements of gold, it is recommmended that said additive be em the subgroup B of the ?rst group of the periodic system. ployed in extraordinary cases only, say, in making semi its composition being as follows: conductor devices. Cu — 2 percent W -— 5 percent EXAMPLE 8. Hf — balance (93 percent). When making carbide tools the present alloy should EXAMPLE 3. possess not only a low melting point but also satisfac tory impact strength, ductility and a suitable thermal An alloy for brazing lanthanum hexaboride with mo coef?cient of expansion. Thus, an alloy of the following lybdenum in vacuum-tube apparatus, the resulting con composition is employed for connection of parts and nection having to operate at temperatures of up to components based upon tungsten carbide and cobalt l500°C with a good electrical contact obtained. To the with those made of stainless steel: alloy should be added up to 8 percent Cu or Ag, this ad Cu — 25 percent .ditive increasing the electric conductivity of the con 20 La — 3 percent nection about L5 times, whereas for approximating the Co — 5 percent properties of the material of the connection with those of the components being connected, 1 percent Yr and Hf —- balance. 2 percent W are added. Thus the alloy has the following The alloys of the compositions speci?ed hereinabove composition: 25 can be made by the method of powder metallurgy. To Cu — 8 percent this end a calculated amount of the alloy constituents Zr — 1 percent taken in a powdery state is mixed with 20 weight per W — 2 percent cent of ethanol. the resultant mixture is agitated until a Hf — balance (89 percent). uniform coloring appears, whereupon it is dried at a temperature of from 40° to 60°C for 5 or 6 hours. Then EXAMPLE 4. the dried mixture is rubbed throgh a screen No. 0.056 An alloy for connection of ceramics based upon alu and pressed in a steel compression mold at a pressure minum oxide with molybdenum and having a melting of 50 kg per sq.cm. Next the samples obtained are sin point between 1250'” and l300°C at a maximum work' tered for 1 hour under vacuum of not lower than l0‘2 ing temperature of the joint equal to 1000°C. The alloy 35 mm Hg. This done. the samples are mechanically disin has the following composition: tegrated until such a size of particles is obtained that is Cu - 16 percent the most suitable in every particular case but not Cr — 2 percent smaller than 1 mm. since in the case of smaller particles Ti — 5 percent of the alloy some undesirable side effects occur (inter Hf — balance (77 percent). 40 reacttion of the alloys with the surrounding atmo sphere, if brazing does not proceed under vacuum. EXAMPLE 5. etc.). The herein‘disclosed alloy is employed in the An alloy for connection of materials featuring rela shape of dispersed particles having a conventional di tively low melting point such as cobalt silicide with ameter of not less than 1 mm. manganese silicide. The melting point of the alloy being 45 The dispersed particles of the alloy are applied to the within the range of from l000° to ll00°C, the maxi place to be connected. whereupon it is given a heat of mum working temperature of the connection must be up to the melting point of the alloy ( 1200° to I900°C) not below 900°C since these materials have to operate under vacuum not below 10‘2 mm Hg, in an inert or re in media at temperatures of up to 800°C. In addition, ducing atmosphere. Once the alloy is molten, it must be the alloy should possess the maximum possible electric kept l to 3 min in that state. The surface of the dis conductivity and chemical resistance. All the above re persed particles of the alloy and the parts being brazed quirements are met by the following composition of the together need be neither carefully ground nor cleaned alloy: and degreased. Ag —— 26 percent The present alloy can be obtained by another Nb — l percent method, e.g.. by alloying the components in an arc or Ni — 1.5 percent resistance furnace in an atmosphere of argon or under Mn — l percent vacuum. Hf —- balance (70.5 percent). Some materials that cannot be connected together by applying present-day techniques such as boron car EXAMPLE 6. 60 bonitride with tungsten. boron carbide with boron car If no demands are made for the material of the con bonitride. niobium carbide with boron carbonitride. nection to possess high electric conductivity, then Ag have been brazed together with the use of the brazing as an additive may be replaced by a cheaper material alloy of the following composition (in weight percent): such as copper. Thus, for making diamond tools. use is Cu — l4 made of the following alloy as a bond: 65 Cu - 30 percent Ti — 5 percent Zr — 4 percent Hf — balance (65 percent). 3,903,585 9 10 Brazing temperature l§l40°C under vacuum of l0‘3 scandium. yttrium, lanthanides, carbon, silicon, germa mm Hg. nium. titanium. zirconium. vanadium, niobium, tanta As a result a tight conection 0.2 mm thick has been lum, phosphorous. chromium molybdenum, tungsten. obtained‘ After stretching forces had been applied manganese, technetium. rhenium. ruthenium. osmium, breakage of the test specimen occurred in the bulk of cobalt, nickel, rhodium, palladium, iridium. and plati the boron carbonitride component which is indicative num, in an amount of 2 to 2] percent of the alloy of the fact that the connection of the present alloy with weight wherein said alloy is applied as particles to the the boron carbonitridc proved to be stronger than the latter itself, surface of the materials to be brazed, said particles hav ing a particle size of at least about 1mm diameter. and Thus. on the basis of all described and discussed herein above if can be said that the herein-proposed heated to a melting temperature under a vacuum of at alloy is a versatile one as it is found to be capable of least lO"2mm Hg in an inert or reducing atmosphere. connection of even those infusible materials that hith 2. A method of claim 1 wherein the ?rst component erto could not be connected. Besides, by appropriately is present in an amount of from 20 to 30% of the alloy varying the percentage of additives in the alloy, its weight and the melting point of said alloy is between melting point is controllable within a wide range of |000° to |200°C. temperatures and the most diverse physico-chcmieal 3. A method of claim 1 wherein the ?rst component properties can he imparted thereto. is present in an amount of from [2 to 20% of the alloy What is claimed is: weight and the melting point of said alloy is between l. A method of brazing carbides, borides, nitrides. 20 l200° to [500°C silicides and ceramics to each other and to high melting 4. A method of claim 1 wherein the first component metals comprising brazing said materials in the pres is present in an amount of from 8 to 12% of the alloy ence of a brazing composition consisting essentially of weight and the melting point of said alloy is between an alloy consisting essentially of a major proportion by 1500° to l800°Ct weight of hafnium. a first additive component selected 25 5. A method of claim 1 wherein the first component from the group consisting of copper, gold. silver and is present in an amount of from 2 to 8% of the alloy mixtures thereof. in an amount of from 2 to 30 percent weight and the melting point of said alloy is between of the alloy weight, and a second additive component l800° to 2]OO°C, selected from the group consisting of boron, aluminum, * >k * * * 30

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