NiTi合金微弧氧化复合膜层的制备与性能

Preparation of a composite coating on NiTi alloy based on micro-arc oxidation and its properties

为了提高Ni Ti合金在人体中的耐蚀性,对其表面依次进行掺杂Zn O微粒的微弧氧化(MAO)和聚丙烯酰胺(PAM)溶胶凝胶封孔处理。通过场发射扫描电镜(SEM)、能谱仪(EDS)、表面粗糙度测量仪、涡流测厚仪、电化学工作站等手段考察了膜层的表面微观形貌、元素成分、粗糙度、厚度和电化学特性,并用拉开法测试了PAM膜层的附着力。结果表明,与NiTi合金基体、MAO膜层和掺杂Zn O的MAO(MAO-Zn O)膜层相比,MAO-Zn O/PAM复合膜层具有致密的微观组织,表面更平整(粗糙度Ra=0.565μm),内层和界面电荷转移电阻最大,耐蚀性突出,而且在潮湿状态下拥有一定的自修复能力。

To improve the corrosion resistance of NiTi alloy in human body,the NiTi alloy surface was sequentially subjected to micro-arc oxidation(MAO) doped with ZnO nanoparticles and sol–gel sealing with polyacrylamide(PAM).The surface morphology,elemental composition,roughness,thickness,and electrochemical properties of the prepared coating were studied by using scanning electron microscope(SEM),energy-dispersive spectrometer(EDS),surface roughness meter,eddy-current thickness gauge,and electrochemical workstation.The adhesion of PAM film was tested by pull-off method.The results showed that as compared with NiTi alloy substrate,MAO coating,and ZnO-doped MAO(MAO-ZnO) coating,the MAO-ZnO/PAM composite coating had a compact microstructure,a smoother surface(Ra = 0.565 μm),the largest inner resistance and interfacial charge transfer resistance,outstanding anticorrosion performance,and self-healing ability under the humid condition.