0 19 0 29 carbon and about 0 13 0 25 nitrogen for best results the alloy powder contains about 0 25 0 28 carbon and about 0 15 0 20 nitrogen the preferred method of making the alloy powder is to melt a heat of alloying materials to provide a molten alloy having approximately the following weight percent composition 0 35 max carbon 1 00 max manganese 1 00 max silicon 26 0 30 0 chromium 5 0 7 0 molybdenum 3 max nickel 1 00 max iron and the balance essentially cobalt the preferred melting technique is vacuum induction melting vim although other melting techniques can be used during the melting process the vim furnace is backfilled with a partial pressure of an inert gas such as argon alternatively the vim furnace is backfilled with a partial pressure of a cover gas that contains an inert gas and nitrogen gas in the presence of the inert gas or the cover gas the molten alloy is superheated to a temperature selected to provide a desired level of nitrogen in the molten alloy as is known to those skilled in the art the equilibrium nitrogen solubility in a molten co cr mo alloy is inversely related to the temperature of the molten alloy and directly related to the square root of the partial pressure of nitrogen in the melting vessel the superheated molten alloy is atomized with nitrogen gas so as to provide substantially spherical powder particles the atomized alloy is preferably cooled in an inert atmosphere to prevent excessive nitriding and oxidizing of the powder particles when cooled the alloy powder is screened to a desired particle size and.