采用水热方法在镍钛合金表面一步合成TiO_2-羟基磷灰石纳米薄膜（英文）

One-Step Synthesis of TiO_2-Hydroxyapatite Nano-films on NiTi Alloy by Hydrothermal Method

采用高浓度的CaHPO4和Ca（H2PO4）2溶液对镍钛合金进行一步水热处理,以进行生物活性表面改性。经过处理的试样表面覆盖的薄膜由小晶粒（约70 nm）和大颗粒（100-250 nm）组成。X射线光电子能谱分析表明试样表面的钛以TiO2形式存在,检测不到镍,钙磷元素以磷酸钙存在。处理试样检测到锐钛矿TiO2和羟基磷灰石的X射线衍射峰。在无钙Hank’s平衡盐液中的动电位极化实验表明,处理试样的耐蚀性比抛光试样大大提高。本研究提供的一步法生物活性表面改性方法易于操作,处理温度低,腐蚀性弱,可用于生物医用多孔镍钛合金的表面改性。

NiTi alloy was subjected to one-step hydrothermal treatment in the concentrated CaHPO4 and Ca（H2PO4）2 solutions for bioactive surface modification. Results show that the treated samples are covered by films composed of fine grains（-70 nm） and large particles（100-250 nm）. X-ray photoelectron spectroscopy analysis indicates that Ti at the surface presents as TiO2, Ni is not detectable, and Ca and P exist in the form of calcium phosphate. X-ray diffraction peaks of anatase TiO2 and hydroxyapatite are presented for the treated samples. Potentiodynamic polarization test in a Ca-free Hank＇s balanced solution reveals that the treated sample has a markedly improved corrosion resistance compared with the polished sample. The present work would provide a one-step bioactive surface modification method with easy-operation, relatively low processing temperature and less corrosion, and potentially suitable for biomedical porous NiTi alloy.