DEPARTMENT OF COMMERCE Circular of THE Bureau of Standards S. W. STRATTON, DIRECTOR No. 100 NICKEL MARCH 21, 1921 PRICE, 20 CENTS Printing Office Sold only by the Superintendent of Documents, Government Washington, D. C. WASHINGTON GOVERNMENT PRINTING OFFICE 1921 DEPARTMENT OF COMMERCE Circular OF THE Bureau of Standards S. W. STRATTON, DIRECTOR No. 100 NICKEL MARCH 21, 1921 PRICE, 20 CENTS Sold only by the Superintendent of Documents, Government Printing Office Washington, D. C. WASHINGTON GOVERNMENT PRINTING OFFICE 1921 NICKEL CONTENTS Pag© Introduction 4 Part A. Nickel 5 I. Sources, metallurgy, refining 5 II. Commercial grades—uses and applications 10 III. Statistics of production 13 IV. Metallography 14 V. Chemical properties 17 VI. Physical properties 18 1. Density 18 2. Change of state 18 3. Specific heat 19 4. Thermal expansivity 20 5. Thermal conductivity 20 6. Electrical resistivity 20 7. Thermoelectromotive force 23 8. Magnetic properties 23 Electrolytic-solution potential passivity 9. ; 23 10. Optical properties 25 11. Elasticity 26 12. Hardness 27 13. Tensile properties 27 VII. Effect of impurities on the properties of nickel 28 VIII. Technology 32 1. Casting 32 2. Rolling, forging, annealing 33 3. Welding and soldering 35 4. Electrodeposition 36 Part B. Alloys of nickel 39 IX. Equilibrium of binary alloys of nickel 39 X. Commercial alloys 40 1. Monel metal: () Metallography 42 () Uses and applications 42 (c) Physical properties 44 2. Copper-nickel alloys 50 3. Copper-nickel-zinc alloys; nickel silver (nickelene) 55 4. Ferronickel alloys: (a) Nickel steels 62 ( b ) Invar and related alloys 70 5. Alloys for electrical purposes 71 6. Acid-resisting alloys 78 7. Miscellaneous alloys 79 Part C. Appendixes 85 1. Definitions of physical terms 85 2. List of United States patents on nickel alloys (1900-1920) 89 3. Typical specifications for nickel alloys 91 4. Bibliography 94 3 4 Circular of the Bureau of Standards INTRODUCTION The Bureau is continually in receipt of requests for information concerning the properties, statistics, and manufacture of metals and of alloys, coming from other departments of the Government, technical or purchasing agents of manufacturing firms, or from persons engaged in special investigative work in universities and private technical institutes. Such information is rarely to be found in systematic form usually the sources of such information ; are difficult of access, and their accuracy not always certain. Often quoted information of this sort is valueless, either for the reason that the data upon which it is based are actually incorrect or that they have not been properly interpreted. There are, therefore, being issued from time to time in response to these demands circulars on individual metals or alloys, with the idea of grouping in these circulars all of the best information which the Bureau has as a result of its tests and investigations, together with that available in all records of published tests and investiga- tions of such material. The circulars deal primarily with the physical properties of the metal or alloy. All other features, except a few statistics of pro- duction and such as methods of manufacture, presence of impuri- ties, etc., are discussed only in their relation to these physical prop- erties. It must be realized that the physical properties of metals and alloys are often in great degree dependent upon such factors, so that the statement of values for such properties should include accompanying information regarding these factors by which the properties are affected. The endeavor, therefore, in the circulars is to reproduce only such data as have passed critical scrutiny and to qualify suitably in the sense outlined above all statements, numerical or otherwise, made relative to the characteristics of the metal. The probable degree of accuracy of data is indicated or implied by the number of significant figures in the values given. The Bureau has received much valuable assistance and infor- mation in the preparation of this circular from The International Nickel Co., the American Brass Co., the Scovill Manufacturing Co., the Driver-Harris Co., the Electrical Alloys Co., the Hoskins Manufacturing Co., and others, for which it wishes to express its grateful appreciation. , Nickel 5 PART A. NICKEL I. SOURCES, METALLURGY, REFINING The ores from which commercial nickel is obtained are of three classes: (i) Sulphides, represented by the pyrrhotite-chalcopyrite ores of Sudbury, Canada, and of Norway, and which contain from i to 3 per cent each of copper and nickel, with pentlandite as the nickel carrier; (2) silicates and oxidized ores, which are found prin- cipally in New Caledonia and contain from 5 to 6 per cent of nickel (plus cobalt), with gamierite as the principal nickel carrier; and (3) arsenical ores, which are found in Canada and on the Continent (Saxony) and elsewhere. Of these the first two classes only are of much commercial importance, and the first class furnishes by far the greater proportion of the present output of this metal. In addition to the metal produced from these ores, a small amount of nickel is recovered annually from blister copper. Sulphide ores are roasted and smelted in the blast furnace to a matte containing approximately 24 per cent of nickel plus copper, 45 per cent of iron, and the balance sulphur. This matte is then blown in a converter to one containing essentially only nickel, copper,and sulphur, which is ready for the refining. Although the smelting practice of the companies operating with sulphide ore of the Sudbury type is essentially the same, as well as the product (which is usually known as Bessemer matte) the refining of this matte to metal and the separation of the nickel and copper are accomplished by quite widely different processes, of which the following three are the most important: (1) The Hybinette process, which is in operation in Norway, is essentially an electrolytic one. The matte is roasted to remove the bulk of the sulphur and leached with 10 per cent sulphuric acid, whereby a large proportion of the copper with very little nickel is dissolved out. The residue is melted and cast into anodes, containing about 65 per cent nickel and from 3 to 8 per cent of sulphur, from which, by a combination of electrolysis and cementation of the copper by waste anodes, nickel cathodes and both cement and cathode copper are obtained. (2) In the Mond process, which is operated in England, the Bessemer matte is first roasted and the copper removed in part by leaching with sulphuric acid with the formation of a solution of copper sulphate. The residue, containing nickel oxide with some copper oxide and iron, is reduced at a low heat to a finely- 6 Circular of the Bureau of Standards divided metallic powder. This is carefully protected from con- tact with the air, and carbon monoxide is passed over it at from 50 to 8o° C. At these temperatures nickel-carbonyl vapor is formed and is decomposed by passing it through a tower contain- ing shot nickel heated to about 200° C a layer of nickel is formed ; on the shot, and the carbon monoxide is regenerated and returned to the volatilizing towers. The nickel shot is alternately exposed to and withdrawn from the action of this gas, and in this way a series of concentric layers of nickel are built up around the original nucleus, like the coats of an onion. Mond-nickel shot may readily be distinguished by hammering it upon an anvil, when the various coatings will be broken open, revealing its layer structure. (3) The Orford process, which is the oldest process for the sepa- ration of copper and nickel, is being operated in this country. The Bessemer matte is melted with salt cake, or niter cake, to- gether with coke, in the blast furnace. The sodium sulphide formed by the reduction of the sodium sulphate by the coke, to- gether with the copper sulphide, forms a matte of low specific gravity. The product of the blast furnace is allowed to cool in pots, in which a separation occurs, the upper portion or “tops” containing the greater part of the copper sulphide together with the sodium sulphide, the lower portion or “bottoms” containing the greater part of the nickel sulphide. The “tops” and “bot- toms” are readily split apart when cold. Several treatments are required to effect a sufficiently complete separation. The “tops” go to the copper cupola and converter, where they are blown to blister copper. The “bottoms,” consisting, essentially, of nickel sulphide or matte, are roasted and leached alternately until they have been completely changed to nickel oxide. This is reduced with charcoal in crucibles or reverberator}" furnaces to metallic nickel at a temperature above its melting point, such that the resulting product may be cast into ingots, or blocks, or poured into water to form shot. Electrolytic nickel is also produced by casting this reduced metal at once into anodes and obtaining pine nickel cathodes from them by electrolysis with an electrolyte of nickel sulphate. The silicate ores of New Caledonia, which contain no sulphur, are first mixed with sulphur-bearing materials, such as gypsum or pyrites, and smelted in the blast furnace to a matte, which is shipped for refining, which in this case, in the absence of copper, consists merely of roasting the nickel matte to oxide and reducing the oxide with charcoal. Nickel 7 a Nickel Commercial of Grades Various of Composition — 1. 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