Microwave Plasma Nitriding and Carbiding Surface Modification for Nanostructured Diamond Growth on CoCrMo Alloy
S.A. Catledge, S. Chowdhury, D. Hillman and Y.K. Vohra
University of Alabama at Birmingham, US
diamond, CVD, CoCrMo, nitriding, carbiding
Ultra-hard and smooth nanostructured diamond (NSD) coatings have been investigated for orthopedic and dental implant materials in order to improve their lifetime in the body. While NSD coatings have been successfully deposited on titanium-based alloys with excellent adhesion and tribological properties , the same cannot be said for CoCrMo alloy. This is due to the dominant presence of cobalt which is has a high propensity to form graphite due to its high solubility and catalytic activity with carbon. Subsequently, diamond film adhesion suffers. The goal of this research is to provide surface modification of CoCrMo alloy by plasma nitriding and carbiding techniques. By these methods, we have been able to induce a porous “brain coral” surface morphology which is expected to provide a mechanical interlocking effect with the deposited diamond layer for improved adhesion of the NSD film. In addition, the formation of thick interfacial nitrides or carbides is expected to minimize catalytic reaction of cobalt with carbon, thus allowing growth of NSD without graphite.
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Nanotech 2006 Conference Program Abstract