GB574583A - Process for making metallic alloys - Google Patents

Abstract

574,583. Obtaining coherent masses from powdered metal; alloys. TELEPHONE MANUFACTURING CO., Ltd., and PADDLE, L. H. Jan. 8, 1944; No. 395. [Class 82 (i)] An alloy of two or more metals is made by mixing powder of the metals in the required ratio, pressing into a compact mass, heating until inter-diffusion, without any melting, makes the mass homogeneous, cooling, and then reducing to powder mechanically. An embrittling agent may be mixed with the metal powders, e.g. 0.05 to 0.25 per cent of sulphur with metal powder consisting of 81 per cent of nickel, 17 of iron and 2 of molybdenum, the iron and nickel having been produced, if desired, by the carbonyl process. This may be pressed to form a bar or ring by a pressure of 50 tons per square inch and then heated to 1100-1200‹ C. for 1-4 hours in hydrogen. The mass is then quenched in de-aerated water and crushed in a ball or impact mill. If required for loading and other induction coils, the cores of the powder may then be annealed. For the cores of coils for electrical wave filters 86 per cent of hydrogen-reduced or decarburisedcarbonyl-type iron powder may be mixed with 9.5 of silicon and 4.5 of aluminium and treated as before. For cores of permanent magnets, nickel, aluminium and cobalt in the recognised ratios may be used with 0.1. to 0.25 of iron oxide as embrittling agent. If a very fine powder is desired, the period of heating should not extend beyond that required for complete inter-diffusion. For a complex alloy or one in which the separate metals have widely different melting points, an alloy powder of some of the constituents is first made as above and then another constituent or constituents is or are added and the process repeated., except that the final crushing may be omitted if desired..