Low alloy steel powder for plasma deposition having solid lubricant properties

Abstract

An iron or copper based metal powder useful for plasma deposition of a coating that has a dry coefficient of friction 0.75 or less and readily conducts heat through the coating. The powder comprises (a) H.sub.2 O atomized and annealed particles consisting essentially of (by weight) carbon 0.15-85%, oxygen 0.1-0.45%, an air hardening agent selected from manganese and nickel of 0.1-6.5%, and the remainder iron or copper, with at least 90% of the particles having oxygen and iron or copper combined in the lowest atomic oxygen form for an oxide of such metal. A method of making anti-friction iron powder that is economical, selectively produces FeO and promotes fine flowable particles. The method comprises (a) steam atomization of a molten steel that excludes other oxygen, the steel containing carbon up to 0.4% by weight to produce a collection of comminuted particles, and (b) annealing the particles in an air atmosphere for a period of time of 0.25-2.0 hours in a temperature range of 800.degree.-1400.degree. F. to reduce carbon in the particles to about 0.2% or sponge iron by reducing Fe.sub.3 O.sub.4 or Fe.sub.2 O.sub.3 in CO and (H.sub.2 O steam) to attain nearly all iron with nearly all FeO and 0.1.degree. to 0.85.degree. C.

Dependencies are inferred from the claim text.