| 摘要 |
The behaviour of the a/ß Ti6A14V and Ti6A17Nb alloys and of the a, c.p. Ti upon spark anodisation in H2SO4, H3PO4 and mixtures of these acids is presented. Chemical depth profiling reveals purified oxides with respect to the substrate alloying elements. This is particularly pronounced on Ti-alloys spark anodized in H2SO4ZH3PO4 mixtures, with Al decreasing continuously towards the surface, and V and Nb remaining hardly detectable in the outermost 200 nm. In addition, the incorporation of S was significantly reduced in mixed electrolytes, while about 8 at-% P was incorporated. A novel oxide morphology with "worm-like" features in the µm-range, very different from well-known nano/micro-porous oxides, was found in mixed electrolytes under optimized conditions. A similar but more porous-like structure is formed on c.p. Ti. Raman measurements indicate the presence of mixed anatase, rutile and brookite phases on anodized Ti-alloys. Bond strengths of 34 MPa for worm-like and 40-50 MPa for nano/micro- porous morphologies as well as excellent abrasion behaviour characterized the mechanical properties of the oxides. The compatibility of grit-blasting and etching of surfaces with the spark anodisation process for creating multi-topography surfaces is confirmed. |
