The necessity to substitute functionally disordered hard tissues like bone and teeth with the orthopedic implant instrumentations like artificial hip joints and dental implants is growing because the population of old persons is rapidly increasing. New β-type titanium alloys composed of non-toxic elements with high strength and low modulus of elasticity were, therefore, designed. In general, it is known that the wear resistance of conventional biomedical titanium alloys are lower than that of conventional biomedical alloys like Co-Cr alloy and SUS 316L stainless steel. Friction wear of orthopedic implant materials is a significant clinical problem. The loosen orthopedic implants cause pain and restricted action. Friction wear characteristics of the newly designed β-type titanium alloys and typical conventional biomedical alloys like Ti-6A1-4V ELI, Ti-6A1-7Nb and SUS 316L stainless steel were, therefore, evaluated in air and Ringer's solution using a ball-on-disc type friction wear testing system in this study.
As compared to the conventional biomedical titanium alloys like Ti-6A1-4V ELI and Ti-6A1-7Nb, the newly designed β-type titanium alloys show excellent wear resistance when zirconia ball is used as a mating material, while opposite trends are observed when alumina ball is used as a mating material in air and Ringer's solution. The adhesion and exfoliation of wear particles on the wear grooves and plastic defor-mation of substrate under the wear grooves were observed in the newly designed β-type titanium alloys. It is considered that the different wear mechanisms will be main cause for different wear characteristics between the newly designed β-type titanium alloys and conventional biomedical titanium alloys like Ti-6A1-4V ELI and Ti-6A1-7Nb.
