GB919052A - Improvements in or relating to the manufacture of sintered metallic bodies - Google Patents

Abstract

A sintered metallic body consisting of a matrix metal such as Ni, Fe, Co, W, Mo, Pb, Ag or their alloys, and not more than 2% of a dispersed refractory oxide such as Al2O3, SiO2, MgO and BeO is formed by coprecipitating from a mixed solution of a soluble compound of the matrix metal and a soluble compound of a metal which forms the refractory oxide, a mixture of the matrix metal oxide and the refractory oxide and/or compounds which form the oxides on heating, heating to decompose said compounds and then heating the oxides in a reducing atmosphere to form a powder mixture of the matrix metal and the refractory oxide which is then pressed and sintered. Aqueous solutions such as nitrates of the matrix metal and the refractory metal oxide are used and precipitation of hydroxides, carbonates, oxalates or decomposable basic salts is effected by the addition of aqueous solutions of alkali metal or ammonium hydroxides, carbonates, oxalates or oxalic acid. Alternatively, precipitation is effected by boiling the mixed solution. The precipitate formed is dried, heated to 500 DEG C. in air, crushed to minus 200 mesh, reduced in hydrogen to form a mixture of matrix metal and refractory oxide which is then compacted at 10-50 t.s.i. and sintered below the melting temperature of the matrix metal in vacuum, hydrogen or nitrogen. The sintered compact may be coined and resintered and cold rolled, annealed and drawn into wire. Specification 919,051 is referred to.