DIAMOND-COATING OF METAL ALLOYS

A NOVEL INTERLAYER IS PROPOSED TO ALLOW HIGHER QUALITY DIAMOND COATINGS TO BE DEPOSITED ON STEEL SUBSTRATES THAN HAS PREVIOUSLY BEEN ACHIEVED. STEEL ALLOYS HAVE PRESENTED PARTICULAR DIFFICULTY FOR THE DEPOSITION OF HIGH QUALITY DIAMOND BECAUSE OF CHEMICAL INCOMPATIBILITY AND A LARGE DIFFERENCE IN THERMAL EXPANSION PROPERTIES. THIS HAS BEEN ADDRESSED IN PREVIOUS WORK FOR DIAMOND-LIKE CARBON (DLC) FILMS, BUT WITH LIMITED ADHESION STRENGTH. IN THIS EFFORT, HIGH QUALITY DIAMOND WILL BE DEPOSITED ON STEEL USING THE RESULTS OF RESEARCH ON COATING A COMMERCIAL TITANIUM ALLOY. THE PROCESS CONDITIONS WILL BE DETERMINED FOR DIAMOND-COATING A STEEL ALLOY FOR BEARING APPLICATIONS. THE MECHANICAL PROPERTIES OF COATED COUPONS ARE BEING DETERMINED. FRICTION AND WEAR TESTING ARE BEING PERFORMED ALONG WITH MEASUREMENT OF THE FILM CRACKING STRESS, INTERFACE FRACTURE TOUGHNESS, AND SUBSTRATE YIELD STRENGTH.