Corrosion of the Titanium and Titanium Alloys for Biomaterials under Fluoride Containing Environment

摘要

The corrosion behavior of pure Ti, Ti-6Al-4V, Ti-6Al-7Nb alloys and new Ti- (0.1-2.0) wt percent Pt (or Pd) alloys in a fluoride containing environment were examined by anodic polarization and corrosion potential measurements. SEM observation was performed before and after immersion in the test solutions. The artificial saliva containing 0.1 percent and 0.2 percent NaF (corresponding to 453 and 905 ppmF) and artificial saliva with a low level of dissolved oxygen were used as the test solutions. In an acidic environment (pH4.0) including fluoride, surfaces were roughened markedly by corrosion for pure Ti and Ti-6Al-4V and Ti-6Al-7Nb alloys, although the surface of Ti-Pt (or Pd) alloys was not affected for the most part. With a low level of dissolved oxygen, surfaces were damaged microscopically by corrosion for pure Ti, Ti-6Al-4V and Ti-6Al-7Nb alloys even with a fluoride concentration included in commercial dentifrices, although the surface of Ti-Pt (or Pd) alloys did not change. The Ti-0.5wt percent Pt (or Pd) alloys were expected to be useful as a new Ti alloy with high corrosion resistance in dental use.