纯钛材离子渗氮后在Hank’s人工模拟体液中的电化学性能

Electrochemical Behavior and Corrosion Resistance of Ion Nitriding Layer on Titanium Substrate in Artificially Simulated Body Solution

为了提高纯钛材的表面硬度及耐蚀性,使之更适应人体环境,对铸态纯钛材表面进行离子渗氮。利用能谱仪、X射线衍射仪、扫描电镜及显微硬度计研究了渗氮钛材的成分、相结构、形貌及硬度,利用动电位极化曲线及交流阻抗谱对比研究了纯钛材及离子渗氮钛材在37℃的Hank’s人工模拟体液中的电化学行为。结果表明:经过650℃渗氮处理后,铸态纯钛材表面形成了17μm的梯度渗氮层,其相组成为α-Ti(N),Ti2N,TiN;表面显微硬度约为(650±20)HV,为铸态纯钛材的2.3倍;离子渗氮钛材的耐蚀性明显提高。

As-cast Ti substrate was ion nitridized so as to increase the surface hardness and corrosion resistance as well as compatibility to human body.The elemental composition,phase structure,and morphology of as-obtained ion nitriding layer were analyzed with an energy dispersive spectrometer,an X-ray diffractometer,and a scanning electron microscope,while its hardness was measured with a hardness meter.Moreover,the electrochemical behavior and corrosion resistance of as-cast Ti substrate and the ion nitriding layer in Hank' s solution of 37 ℃ were comparatively investigated based on measurements of potentiodynamic polarization curves and alternating current impedance spectra.It was found that a gradient ion nitriding layer with a thickness of 17 μm was formed on Ti substrate surface after ion nitriding at 650 ℃.As obtained ion nitriding layer consisted of α-Ti(N),Ti2 N and TiN.Moreover,the ion nitriding layer had a hardness of about(650 ±20) HV,which was 2.3 times as much as that of the Ti substrate,while the Ti substrate after ion nitriding possessed greatly improved corrosion resistance.