Effect of thermal oxidation treatment on surface characteristic and corrosion resistance of Ni-Ti shape memory alloy
Effect of thermal oxidation treatment on surface characteristic and corrosion resistance of Ni-Ti shape memory alloy
复制标题
热氧化处理对Ni-Ti形状记忆合金表面特性及耐蚀性能的影响
DOI：
10.2472/jsms.55.965
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
J. Komotori
中科院分区：
文献类型：
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作者：
Hirokatsu Sugawara;H. Goto;J. Komotori
在本研究中，机械抛光的Ni-Ti合金在N2- 20 vol.%中进行等温氧化O2，温度范围为300至800°C。用场发射扫描电子显微镜（FE-SEM）、X射线能谱仪（EDX）、X射线电子能谱仪（XPS）和X射线衍射仪（XRD）对表面进行了表征。电化学腐蚀测试也使用连接到计算机驱动的恒电位仪的三个电化学电池进行。结果表明，不同处理温度下Ni-Ti合金的氧化行为不同。对于在500°C及以上的温度下TO处理的试样，在氧化物层中观察到无Ni层。在300至500°C范围内的温度下进行TO处理的样品与通过抛光完成的表面相比显示出更高的耐腐蚀性。这是因为TO处理产生了具有非晶结构的厚氧化物层。在高于600°C下进行TO处理的试样显示出非常低的钝化电流密度，但具有较低的点蚀电位。这是因为这些样品被结晶氧化物覆盖。因此，在500°C下的TO处理产生了光滑的保护性无镍氧化物层，这有助于Ni-Ti植入物的良好生物相容性。
In this study, a mechanically polished Ni-Ti alloy was subjected to isothermal oxidation (TO) in N2-20vol.%O2 at temperatures ranging from 300 to 800°C. TO-treated surfaces were then characterized by field emission type scanning electron microscopy (FE-SEM), energy dispersive X-ray spectrometer (EDX), X-ray electron spectroscopy (XPS) and X-ray diffraction (XRD). Electrochemical corrosion tests were also carried out using a three electrochemical cell connected to a computer driven potentiostat. Results showed that Ni-Ti alloy exhibited different oxidation behavior depending on the treatment temperatures. A Ni free layer was observed in the oxide layer for the specimens TO-treated at temperatures 500°C and above. Specimens TO-treated at temperatures ranging from 300 to 500°C showed higher corrosion resistance compared to that of the surface finished by polishing. This was because the TO-treatment created a thick oxide layer with an amorphous structure. Specimens TO-treated at above 600°C showed very low passive current densities, but lower pitting potential. This was because these samples were covered with crystalline oxide. Consequently, the TO-treatment at 500°C produced a smooth protective nickel free oxide layer, which contributes to good biocompatibility of Ni-Ti implants.