Abstract: The invention consists of a process for the production of articles by powder metallurgy including the step of adding powdered mica to the metal powder before compacting and sintering. It also extends to a sintered metal product containing mica, in particular a valve seat insert and a shock absorber piston ring. The quantity of mica is preferably between 0.5% and 2% by weight of the metal.

Abstract: A process for the manufacture of sintered metal articles includes the steps of selecting a prealloy powder having a composition consisting essentially of 10-18% chromium, 2-6% iron, 2-6% silicon, 2-6% boron, 0.5-2% carbon, balance nickel, mixing the prealloy powder with copper powder in an amount equal to between 20% and 50% of the weight of the total of prealloy powder and copper, preferably adding a small percentage of a suitable lubricant, pressing the mixture to form a compact, and sintering the compact in the range 1050.degree.-1100.degree. C. for such a time that the copper and the nickel-rich prealloy only partly dissolve in one another.