Wear properties of Co–Cr–Mo–N plasma-melted surgical implant alloys

This paper examines the feasibility of using metal-on-metal bearings to reduce the wear debris which commonly occurs in UHMWPE (ultra-high molecular weight polyethylene) joint materials in knee replacements. HPPM (high pressure plasma melting) was used to make high nitrogen Co–Cr–Mo implant alloys. The melted ingots were subsequently hot-forged and heat-treated. Sub-size specimens were used to evaluate tensile strength and wear properties. Experimental results indicated that the highest nitrogen content of ingots observed in this study was 0.288 wt.%, presenting better tensile and wear properties than those of specimens with less nitrogen. Homogenization treatment can further improve the wear resistance and ductility of the alloys.