GB893425A - Improvements in or relating to the manufacture of sintered copper bodies - Google Patents

Abstract

A sintered copper body containing less than 1% of a dispersed phase of one or more refractory oxides such as Al2O3, SiO2, MgO, or BeO is formed by precipitating from a solution of a copper salt, a copper compound which on heating forms copper oxide, and precipitating form a solution of a salt of the metal of the refractory oxide a compound which forms the refractory oxide on heating, mixing the precipitates, heating to form the respective oxides, heating the oxides in a reducing atmosphere to from the copper matrix and then compacting and sintering. The precipitation from aqueous solutions of the respective metal salts is effected by the addition of aqueous solutions of alkali metal hydroxides, ammonia, alkali metal carbonates or oxalates and oxalic acid. The mixed precipitates are ground to minus 300 mesh B.S.S. and the decomposition and reduction of the precipitate may be effected in a single operation by heating in a reducing atmosphere. In an example, basic copper sulphate and basic aluminium sulphate are separately precipitated from aqueous solutions of copper sulphate and aluminium sulphate with aqueous ammonia. After mixing, filtering and drying, the precipitates are heated in air at 850 DEG C.-900 DEG C., crushed to minus 300 mesh B.S.S., reduced in hydrogen at 300 DEG C. and then compacted at 35-50 tons p.s.i. and sintered in hydrogen or vacuum at 1040 DEG C.