等离子渗氮对纯钛耐腐蚀性能影响的研究

Anticorrosion Properties of Pure Titanium by Means of Plasma Nitriding Technique

目的:模拟口腔环境,研究在不同pH值(pH=6.8,pH=5.5)的人工唾液中,等离子渗氮对纯钛的电化学腐蚀行为的影响。方法:用Tafel曲线法,在不同pH值人工唾液中测定等离子渗氮对纯钛的自腐蚀电阻、自腐蚀电流密度、自腐蚀电位,并与对照组未等离子渗氮的纯钛进行比较分析。应用扫描电子显微镜(SEM)观察试件表面形貌变化。结果:在同一pH值的人工唾液中,等离子渗氮后纯钛的自腐蚀电阻、自腐蚀电流密度和自腐蚀电位与对照组比较均有显著性差异(P<0.05),pH值降低,纯钛自腐蚀电流密度增大,自腐蚀电阻、自腐蚀电位降低。SEM观察表明,pH=5.5时纯钛表面腐蚀现象更严重。结论:等离子渗氮后纯钛的耐腐蚀性能得到提高,pH值下降,耐腐蚀性能降低。

Objective： To investigate the corrosion resistance porperty of titanium which was implanted with nitrogen using plasma in the artificial saliva in vitro. Methods： Compared with the control groups, electrochemical technique of Tafel curve was used to measure the polarization resistance （ Rp）, current density of corrosion （Icorr） and the corrosion （Ecorr） of Titanium implanted with Nitrogen in the artificial saliva with different pH values. After electrochemical analysis, the mierostrueture was examined by SEM. Results： In the same condition, the Rp of Titanium using plasma was higher than that of the control groups, so was Ecorr （ P 〈 0.05 ）. The results showed that when pH value reduced, Ieorr increased but Rp and Ecorr descended evidently. SEM confirmed that mictostructure was corroded more heavily in the acidic environment than that in the neutral environment. Conclusion ： The anticorrosion of titanium using plasma nitriding was superior to that of titanium without treatment. In the acidic condition, the corrosion resistance of titanium descended evidently.