pH值与F^-对纯钛及含钛镍铬合金在人工唾液中电化学腐蚀的影响

Effect of pH value and fluoride ions on corrosion resistance of pure Ti and Ni-Cr-Ti alloy in artificial saliva

目的:研究不同pH值与F-对纯钛及含钛镍铬合金在人工唾液中电化学腐蚀的影响。方法:使用电化学工作站测量纯钛及含钛镍铬合金在不同人工唾液中的极化曲线,测得纯钛及含钛镍铬合金的自腐蚀电位(Ecorr)、自腐蚀电流密度(Icorr)和极化电阻(Rp),以评价pH值与F-对纯钛及含钛镍铬合金电化学腐蚀的影响。应用场发射扫描电子显微镜(FSEM)观察试件腐蚀前后形貌变化。结果:随着pH值的降低,纯钛及含钛镍铬合金的自腐蚀电位和自腐蚀电流密度增大,极化电阻减小,两者有显著性差异(P<0.05)。在pH=4人工唾液中加入0.2%NaF后,纯钛自腐蚀电位和自腐蚀电流密度明显增大,极化电阻明显减小,两者有显著性差异(P<0.01)。场发射扫描电子显微镜显示,纯钛及含钛镍铬合金表面发生腐蚀,纯钛在含0.2%NaF人工唾液中的腐蚀最为严重。结论:纯钛及含钛镍铬合金的耐腐蚀性随pH值降低有所下降,F-降低纯钛的耐腐蚀性能。

Objective： To investigate the effect of pH value and fluoride ions on the corrosion resistance of pure Ti and Ni-Cr-Ti alloy in the artificial saliva.Methods： Electrochemical technique was used to measure the electric potential of corrosion（Ecorr）,current density of corrosion（Icorr） and polarization resistance（Rp） of pure titanium and Ti-Ni-Cr alloy in the artificial saliva with different pH value and fluoride concentrations.After electrochemical analysis,microstructure and phase diffraction were examined by FSEM.Results： With the lower pH value,the Ecorr and Icorr of pure titanium and Ti-Ni-Cr alloy increased,the Rp decreased,there was a significant difference（P0.05）.The Ecorr and Icorr increased markedly,the Rp significantly reduced in the artificial saliva containing 0.2% NaF（P0.01）.FSEM showed that pure titanium and Ti-Ni-Cr alloy surface corrosion,pure titanium in the artificial saliva containing 0.2% NaF was most serious.Conclusion： Lower pH value decreases the corrosion resistance of pure titanium and Ti-Ni-Cr alloy and the artificial saliva containing fluoride ions decreases the corrosion resistance of pure titanium.