Improvements relating to powder metallurgically produced materials and processes formaking the same

摘要

A powder metallurgically produced material and shaped body thereof consists of about 60-95 per cent stainless steel and a metal or metal alloy selected from copper, silver, tin or alloys of these metals and may be produced by infiltrating the metal or its alloy into a compacted matrix of stainless steel, e.g., of porosity 5-35 per cent. The stainless steel powder used preferably has a particle size all less than 100 mesh and at least half of which is greater than 325 mesh, or having a particle size between minus 100 mesh and plus 200 mesh. The matrix may be pre-sintered and cooled before infiltration. After infiltration the material may be heat treated. Infiltration of tin or tin alloy may be performed at between about 1000 and 1100 DEG C. The stainless steel may be one containing less than about 0.1 per cent of carbon and, e.g., 18 per cent chromium and 8 per cent nickel. A copper alloy infiltrant may comprise 90-93 per cent copper and the balance iron, nickel and/or manganese, e.g., one containing 3-10 per cent nickel. The copper alloy may comprise 60-95 per cent copper, 3-5 per cent iron, 3-10 per cent nickel and 3-10 per cent manganese.