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Surface oxidation of NiTi
来源: 日期2017-12-15 09:59 点击:

报告题目:Surface oxidation of NiTi





Surface oxidation at elevated temperatures has been a phenomenon of interest for NiTi alloys. On one hand it has been deliberately used to provide a surface protective layer to prevent Ni release for biomedical applications, and on the other it is to be minimised in metal processing and production. This study investigated the use of flowing argon as a protective gas for heat treating NiTi at elevated temperatures. It was found that under flowing argon protection, complex oxidation reactions still take place within the surface layers of NiTi. This includes the formation of transient oxides of Ni2Ti4Oand TiOa t lower temperatures, followed by formation of TiNi3underneath the oxide layers, and conversion of TiO to TiO2at higher temperatures. The final product contained a rutile TiO2outer surface, a composite middle layer consisting of Ni(Ti)+TiO2,a TiNi3inner layer and a Ti-depleted zone within the body of the alloy.A diffusion-based theory for the oxidation forming mechanism of NiTiwas introduced. For heating at 1223 K for 24 hours, the surface layers have a combined thickness of ~15 µm and a Ti-depleted zone of ~400 µm within the body of the alloy. The Ti-depleted zone appeared to play a major role in affecting the transformation and mechanical properties of the alloy.


吴志刚,男,1982年1月生,于2011年获得澳大利亚西澳大学博士学位,2011年12月-2012年12月在西安交通大学前沿院进行博士后研究工作,2013年-2015年期间任澳大利亚ALS Global公司材料工程师,2015年-2017年在西澳大学从事博士后研究工作,现任广州大学土木工程学院副教授、先进材料团队负责人、硕士生导师。长期从事形状记忆合金、磁性材料、金属基复合材料和生物应用材料等的研究。已在国际学术期刊上发表论文30余篇,先后主持或参与中国和澳大利亚的科研项目5项。

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