采用水热方法在镍钛合金表面一步合成TiO2-羟基磷灰石纳米薄膜

One-step Synthesis of TiO2-hydroxyapatite Nano-films on NiTi alloy by a Hydrothermal Method

摘要:

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细晶粒(~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。本文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，腐蚀性低，可用于生物医用多孔镍钛合金的表面改性。

Abstract:

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