Study On Surface Anodic Oxidation Of Medical Titanium Alloys

ABSTRACT Tests are conducted to investigate the technics of anodizing colors of TA2 andTi-6Al-4V implantation materials. The various factors that influence coloring effectare studied. The structure and surface elements distribution of anode films areresearched by X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS).The surface morphology of anode films are observed through SEM, at the same time,the corrosion resistance test of anode films is performed in the simulated body fluid. The results on composition, structure, and morphology studies, corrosionexperiment revealed the following conclusions: The electrolyte voltage is the main factor affecting the coloring, and the colorschange with voltage shifting. In the other side, the time of the process, alloy elements,electrolyte solutions and subsequent heat treatments of the materials will influence thecoloring to different extents. But the state of heat treatments of the substrate sampleshave little influence on coloring. The surface elements of TA2 consists of mainly Ti, O and C , and the surfaceelements of Ti-6Al-4V consists of mainly Ti, O , C and Al . The carbon is owed tosurface polluter, and the oxygen is root in surface polluter and crystal lattice oxygen.XRD analysis shows the anode films of TA2 and Ti-6Al-4V are uncrystalline oxidetitanium and can be translated stable crystal structure through heat treatment. Data from scanning electron microscopy(SEM) indicates that there is acompactly and sleekly layer on the surface of anode films, further more, this passivelayer increases resistance and hardness of substrate materials. Data from corrosion experiment in a simulated body fluid reveals that ionsrelease from TA2 and Ti-6Al-4V alloy are retarded and improves corrosion resistance. From the statements above, the coating process provided an effective means forimproving the corrosion resistance and biocompatibility of surgical titanium alloysunder physiological conditions.