UNITED STATES PATENTS ON POWDER METALLURGY UNITED STATES DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS U. S. DEPARTMENT OF COMMERCE W. AVERELL HARRIMAN, Secretary NATIONAL BUREAU OF STANDARDS E. U. CONDON, Director NATIONAL BUREAU OF STANDARDS MISCELLANEOUS PUBLICATION M184 UNITED STATES PATENTS ON POWDER METALLURGY By RAYMOND E. JAGER and ROLLA E. POLLARD Issued July 1 , 1947 UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1947 For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - Price 30 cents PREFACE Patents are disclosures of inventions, in return for which the inventor is given the right to exclude all others from making, using, or selling his invention for the term of 17 years. After this period the invention becomes public property. Patent literature is a valuable source of technical information, for, by these disclosures, the de- velopment of an art may be traced through a long period of time. This publication, based on a collection search of United States patents of the present series, which began in 1836, represents more than a century of progress in the art of powder metallurgy. Patents issued up to January 1, 1947, are included. The collection search was made for the National Bureau of Standards by Invention, Inc., under the direction of Raymond E. Jager, president: R. E Pollard, metallurgist, of the Bureau's staff, edited the abstracts, eliminating those not pertinent to powder metallurgy, and revised the classification. E. U. Condon, Director. n CONTENTS Page. Preface II I. Introduction 1 II. Production of metal powders 1 2 1. Atomization, vaporization, spraying molten metal, or physically contacting it with other fluids, to obtain fine particles 2 2. Chemical precipitation 6 3. Electrical processes, electrolysis, electroplating, etc_ 11 4. Mechanical comminuting of metal to powder by cutting, rolling, crushing, or other mechanical operations 15 5. Reduction of powdered or granulated ores, metal oxides, carbonyls, or other metal compounds by heat, gases, etc 19 III. Handling and working metal powders 25 1. Coating individual grains of powder, with metallic or nonmetallic coatings 25 2. Classifying, separating and purifying metal powders. 26 3. Molding, compressing or briquetting, bonding, and sintering or heat-treating for these purposes 29 IV. Alloying of metal powders 35 1. Alloy powders 35 2. Alloys made by compressing and heating, sintering or reducing mixed powdered constituents 36 3. Alloys employing metal powder as the binding mater- ial for metallic carbides, nitrides, or the like, in the production of very hard articles, such as cutting tools, etc 39 V. Applications of metal powders 50 1. Abrasive tools, other abrasive articles and mate- rials, polishing compositions, employing metal powders 50 2. Bearings and bearing materials 55 3. Chemical processes employing metal powders or employing catalysts which comprise metal pow- ders 62 4. Coating and molding methods and compositions, including paper metallizing, electrical coatings, etc 68 5. Composite articles in which metallic powders are used for facings on a metal backing or as fillers- _ 84 6. Dental amalgams, etc 85 Where the production of metal powders is for a specific application, see also subheads under section V. Ill v CONTENTS V. Applications of metal powders—Continued Page 7. Electrical contacts, brushes, electrodes, battery- parts, resistors, rectifiers, condensers, etc. made with metal powders 87 8. Expanded materials and pressure processes in which metal powder releases the gas 97 9. Explosives and explosive compositions, photo- graphic flash powders, projectiles, bullets, rivets, etc 98 10. Filtering materials and other porous articles 100 11. Friction materials such as brake linings, clutch facings, etc 101 12. Heat-conducting or reflecting material such as for heating elements and insulation, respectively 102 13. Incandescent filaments, wires, cathodes, for tubes, flash bulbs, and the like 2 103 14. Insecticides 112 15. Lubricants and oils 112 16. Magnetic materials and articles 113 17. Miscellaneous articles, e. g., jewelry, chemical dishes, pen points, spectacle frames, small bars and tubes, cigarette mouthpieces and like items. 126 18. Molds and dies 128 19. Packing materials using metal powders 129 20. Pigments, paint, etc. 3 130 21. Printing type and printing plates or the like formed with metal powder 136 22. Refractory materials using metal powders or articles employing refractory metal powders 136 23. Solder and sealing media 4 137 24. Welding rods and compositions 138 See also, "Explosives," section V, 9, for loose photographic flash powders. See also, "Coating and molding," section V, 4, for specific processes. See also, "Packing materials," section V, 19, and "Welding rods and composition," section V, 24. UNITED STATES PATENTS ON POWDER METALLURGY By Raymond E. Jager and Rolla E. Pollard ABSTRACT A total of 2,253 United States Patents pertaining to powder metallurgy are classified under four main headings: production, handling and working, alloying, and applications. Under these main headings, the patents are listed by number in chronological order, together with the name of the inventor and a short abstract of the patent. Patents issued up to January 1, 1947, are included. I. INTRODUCTION Patent literature is a valuable source of technical information that undoubtedly would be more widely used if compiled listings of all patents relating to a particular subject were available. Unfortunately, a collection search of patents is a laborious and time-consuming job that requires expert knowledge of the intricacies of the United States Patent Office classification system. It is the purpose of this report to provide a comprehensive list of patents relating to powder metallurgy, classified in related groups and with a short abstract of each invention, to simplify the study of patent literature on this subject. The collection search on which this report is based was exhaustive, and the report, therefore, covers the field of powder metallurgy, com- prehensively. More than 50 subclasses in the United States Patent Office were searched thoroughly and nearly one hundred fifty other subclasses were examined. All patents issued since September 1942, regardless of classification, have been examined and those relating to powder metallurgy have been included in the report, up to January 1,1947. The term "powder metallurgy' ' usually is applied to the art of mak- ing objects by pressing and heating metal powders which may or may not contain nonmetallic additions. This excludes some of the most important industrial uses of metal powders such as paint pigments, metallic coatings, catalysts, etc. However, the methods of produc- tion, handling and classification of metal powders are very much the same whether the powder is used as such or is pressed and sintered. For this reason, some of the applications named above are included in the report. Many metallurgical processes in which metal powders are produced as a step in refining or processing ores are omitted. The machines used in powder metallurgy, such as grinding mills, presses, briquetting machines, furnaces, etc. generally are omitted because in most cases they were obtained from other arts with little structural change. However, some machines developed for particular applica- tions of powder metallurgy, such as bearings or magnetic dust cores, are included. Most of the devices used in testing metal powders such 1 2 Miscellaneous Publications, National Bureau of Standards as sieves, flow meters, turbidimeters, air separators, etc. also were borrowed from other arts and generally are omitted unless developed particularly for metal powders. Classification of 2,253 patents would be difficult even in a less heterogeneous field than powder metallurgy. However, an attempt has been made to organize the report so that the patents on a given phase of the art can be ascertained by use of the table of contents. It will be noted that the patents are classified under four main head- ings: Production, handling and working, alloying, and applications. Subheadings under each of these are in alphabetical order according to the first, or key, word. Under each of the subheadings the patents are arranged in numerical order according to the patent numbers, which means that they are also in chronological order. Many of the patents might be classified in any one of several classes. However, as each patent is listed in only one place, the classification has been arranged whenever possible according to the final product. In other words, those of a general nature are placed under the first three head- ings while those pertaining to a particular article are placed under Applications. An exception to this will be noted in Section IV, 3, wherein, under a general heading describing very hard metal compo- sitions, are listed such particular products as cutting tools so that most of these closely related applications may be found in one group. II. PRODUCTION OF METAL POWDERS 1. Atomization, Vaporization, Spraying Molten Metal, or Physically Contacting It With Other Fluids, To Obtain Fine Particles U. S. Patent Patentee Subject No. Feix 15, 733 Melted metal granulated by rotary motion in cold water. Perry _ 99, 588 Molten iron granulated by stream of cold water. Wood 143, 485 Molten slag or cast iron granulated by con- tinual motion of water. Small 282, 579 Comminuted solder made by running molten solder in blast of air. Randolph 305, 758 Stream of cold water projected against stream of molten alloy or solder. Bosworth 373, 766 Jet of steam forced on molten lead decreases oxidation, present with blast of air. Tilghman 446, 986 Chilled iron globules made by atomization using high-pressure steam or gas; alkali used to prevent rust. Tilghman__ 446, 987 Same as 446,986, except drying is accom- plished in nonoxidizing atmosphere. Madden 702, 736 Melted fusible material sprayed from rotat- ing vessel. Pohl 706, 475 Material melted, sprayed into a retort, evaporated and condensed. Bertou 719, 725 Liquefied metal mixed with an elastic fluid, such as superheated steam at high pres- sure; pulverization obtained upon sudden expansion.