酸化防止を考慮したチタンの鏡面ポリシング加工技術の開発

抄録

Since titanium has a corrosion resistance and biological compatibility, it has recently been used in aeronautics and biomedical fields such as the development of artificial bone, medical tools and equipment. These specific applications often require a mirror-like surface in order to achieve an optimum efficiency and quality. However conventional polishing processes actively oxidize the polished surface and consequently the surface roughness isn't improved because of the presence of several surface oxides. Therefore a new polishing technology process that countermeasure oxidation during polishing of titanium was developed and evaluated. Firstly, new slurry was developed for the countermeasure against oxidation. L-ascorbic acid (also known as vitamin-C) was added to the slurry for the countermeasure against oxidation because it is frequently used as antioxidizing agent. Furthermore, xanthan gum was also added to the slurry as viscosity increasing material that allowed a better diamond grain dispersion in slurry. Here, respective optimum additive amount of L-ascorbic acid and xanthan gum were revealed. And surface roughness of titanium was improved by removing chips every feed by using developed slurry. Moreover, period of antioxidant effect of developed slurry was evaluated. Finally, corrosion resistance regarding titanium in developed slurry was performed. It is concluded from the results that (1) the slurry containing L-ascorbic acid and xanthan gum allowed and oxidation-free polishing, (2) polishing process without deep scratches was carried out by removing chips with sandpaper, (3) surface roughness of titanium was improved up to Rz 0.12 μm by using developed slurry, (4) developed slurry had antioxidant effect period of one week, (5) titanium submerged period of one month in slurry containing L-ascorbic acid and xanthan gum didn't erode.