MANUFACTURE OF COMPOSITE MATERIAL

PURPOSE:To easily and economically manufacture a metallic composite material excellent in wear resistance, by subjecting the porous body of alloy having a specific pore diameter and containing specific amounts of Cr to heat treatment in an oxidizing atmosphere and then by impregnating a molten metal into the pores. CONSTITUTION:The porous body of alloy having 0.05-4mm average pore diameter and preferably having >=about 50mum skeleton thickness and containing 10-50wt% Cr is held at >=600 deg.C, preferably about 600-1,200 deg.C, in the air or in the oxidizing atmosphere such as oxygen-enriched air, etc. The above porous body can be formed of foamed metal. By the above heat treatment, the surface of three-dimensional reticular skeleton of the above porous body is uniformly formed into chromium oxides of about Hv2,000 hardness. Then, molten cast iron or molten aluminum alloy is impregnated into the pores of the porous body after the above heat treatment. The above-mentioned impregnation can be carried out by means of a simple casting process such as die casting, etc. Since this impregnated metal firmly holds the skeleton of the above-mentioned highly hardened porous body, a metallic composite member excellent in wear resistance can be formed.