Oxidation resistant diamond composite and method of forming the same

Abstract

The improved diamond composite (10) exhibits increased oxidation resistance at elevated temperatures, as well as anti-reflective properties. The composite (10) includes a diamond (12), the surfaces (14) of which are protected by an adherent coating (16) consisting essentially of a layer (18) of hafnium carbide adhering and chemically bonded to the diamond (12), a layer (20) of hafnium oxy-carbide adhering and chemically bonded to the hafnium carbide layer (18) and an oxidation-resistant layer (22) of hafnium oxide adhering and chemically bonded to the hafnium oxy-carbide layer (20). Preferably, the coating (16) is sufficiently thin so that it or at least the hafnium oxide layer (22) thereof has about one-quarterwavelength thickness. The method of forming the composite (10) employs sputtering hafnium metal in an argon atmosphere, preferably at about 100.degree.150 degrees Celsius, to form the hafnium carbide layer (18), then continuing the sputtering in an oxygen and argon mixture to first form the hafnium oxy-carbide layer (20) and then the hafnium oxide layer (22). The sputtering is followed by heat treating the composite (10) in an oxygen atmosphere at preferably about 350-450 degrees Celsius for about 4-24 hours to assure full utilization of the hafnium metal. This method is simple, inexpensive and effective.

Dependencies are inferred from the claim text.