GB669570A - Improvements in or relating to metal powder material suitable for powder metallurgical operations - Google Patents

Abstract

A method of preparing metal powder for subsequent powder metallurgical operations comprises coating individual particles of a relatively soft and malleable metal powder with a different metal by deposition from a solution, and heat treating the powder at a temperature below the melting temperature of the coating but high enough to cause intercrystalline penetration without substantial alloying. The coating may be made by chemical deposition or electrolytically. In one example Fe powder is coated with 2 per cent Ni by deposition from a solution of nickel chloride and the coated powder annealed in a hydrogen atmosphere at 1400-1600 DEG F. for 15-60 minutes. In another example, the Fe powder is coated with 4 per cent Cr by deposition from a solution of copper oxalate and annealed in a hydrogen atmosphere at 1400 DEG F. for 15 minutes. Further, the iron powder may be coated with 4 per cent Cu and 2 per cent Ni by immersion in the solutions given above in turn and then annealed in a hydrogen atmosphere at 1400 DEG F. for 15 minutes to form a Cu-Ni alloy coating. 1 per cent of graphitic carbon may be added to each of these coated powders before compacting under heat and pressure.