Sittig C, Textor M, Spencer N D, Wieland M, Vallotton P H
Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, Sonneggstr. 5, CH-8092 Zürich, Switzerland.
J Mater Sci Mater Med. 1999 Jan;10(1):35-46. doi: 10.1023/a:1008840026907.
The biocompatibility of commercially pure titanium and its alloys is closely related to their surface properties, with both the composition of the protecting oxide film and the surface topography playing an important role. Surfaces of commercially pure titanium and of the two alloys Ti-6Al-7Nb and Ti-6Al-4V (wt %) have been investigated following three different pretreatments: polishing, nitric acid passivation and pickling in nitric acid-hydrogen fluoride. Nitric acid treatment is found to substantially reduce the concentration of surface contaminants present after polishing. The natural 4-6 nm thick oxide layer on commercially pure titanium is composed of titanium oxide in different oxidation states (TiO2, Ti2O3 and TiO), while for the alloys, aluminium and niobium or vanadium are additionally present in oxidized form (Al2O3, Nb2O5 or V-oxides). The concentrations of the alloying elements at the surface are shown to be strongly dependent on the pretreatment process. While pickling increases the surface roughness of both commercially pure titanium and the alloys, different mechanisms appear to be involved. In the case of commercially pure titanium, the dissolution rate depends on grain orientation, whereas in the case of the two alloys, selective alpha-phase dissolution and enrichment of the beta-phase appears to occur.
工业纯钛及其合金的生物相容性与其表面性质密切相关，其中保护性氧化膜的组成和表面形貌都起着重要作用。对工业纯钛以及Ti-6Al-7Nb和Ti-6Al-4V（重量百分比）这两种合金的表面进行了三种不同预处理后的研究：抛光、硝酸钝化以及在硝酸 - 氢氟酸中酸洗。发现硝酸处理能大幅降低抛光后表面污染物的浓度。工业纯钛上天然的4 - 6纳米厚氧化层由不同氧化态的氧化钛（TiO₂、Ti₂O₃和TiO）组成，而对于合金，铝和铌或钒还以氧化形式（Al₂O₃、Nb₂O₅或钒氧化物）存在。结果表明，表面合金元素的浓度强烈依赖于预处理工艺。虽然酸洗会增加工业纯钛和合金两者的表面粗糙度，但似乎涉及不同的机制。对于工业纯钛，溶解速率取决于晶粒取向，而对于这两种合金，似乎发生了α相的选择性溶解和β相的富集。
