Fabrication of duplex coatings on biomedical titanium alloys by plasma nitriding, metal plasma immersion ion implantation, and reactive plasma oxidation

Summary form only given. In order to make titanium oxide films that possess good blood compatibility and can withstand a high contact stress, we are using a novel hybrid plasma fabrication technique combining plasma nitriding and plasma immersion ion implantation (PIII). The titanium alloys are first nitrided in a nitrogen plasma and then the TiO/sub x/ coating is produced by plasma immersion ion implantation utilizing titanium metal plasma and reactive plasma oxidation. The Ti-N layer produced by plasma nitriding can withstand a high contact stress and the titanium oxide coating generated by PIII yields improved biocompatibility and tribological properties. In this paper, the plasma fabrication processes are described. In addition, the tribological properties are assessed by measuring the microhardness and wear resistance, whereas the microstructures and surface characteristics are evaluated by using glancing X-ray diffraction, atomic force microscopy, and transmission electron microscopy. Our results show that titanium alloys with surface duplex PIII-TiO/sub x//Ti-N films have better load bearing capacity than that of PIII-TiO/sub x/ films.