中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 19 No. 3 June 2009 |
（1. Jiangsu Key Laboratory for Advanced Metallic Materials, School of Materials Science and Engineering,
Southeast University, Nanjing 211189, China;
2. School of Public Health, Southeast University, Nanjing 210096, China;
3. Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, China）
Abstract:A modified advanced oxidation process(AOP) utilizing a UV/electrochemically-generated peroxide system was used to fabricate titania films on chemically polished NiTi shape memory alloy(SMA). The microstructure and biomedical properties of the film were characterized by scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS), inductively-coupled plasma mass spectrometry(ICPMS), hemolysis analysis, and blood platelet adhesion test. It is found that the modified AOP has a high processing effectiveness and can result in the formation of a dense titania film with a Ni-free zone near its top surface. In comparison, Ni can still be detected on the outer NiTi surface by the conventional AOP using the UV/H2O2 system. The depth profiles of O, Ni, Ti show that the film possesses a smooth graded interface structure next to the NiTi substrate and this structure enhances the mechanical stability of titania film. The titania film can dramatically reduce toxic Ni ion release and also improve the hemolysis resistance and thromboresistance of biomedical NiTi SMA.
Key words: NiTi shape memory alloy; titania film; advanced oxidation process(AOP); biomedical properties
