氯离子对2种牙科常用合金耐腐蚀性的影响

摘要

Objective: To investigate the effect of chloride concentration on the corrosion of Co-Cr alloy and pure Ti in a simulated oral environment. Methods: The electrochemical corrosion tests of pure Ti and Co-Cr alloy were carried out in neutral artiifcial saliva solutions with different NaCl concentrations (0.9%, 2.0%, and 3.0%). hTe morphologies of corroded surface for pure Ti and Co-Cr alloy were observed by scanning electron microscope (SEM). Results: hTe changes in the self-corrosion potentials (Ecorr) for pure Ti and Co-Cr alloy in three kinds of artificial saliva solutions was not obvious. However, the self-corrosion current densities (Icorr) of pure Ti were much lower than those of Co-Cr. TheIcorr of Co-Cr alloy increased in a concentration-dependent manner of NaCl, whereas the breakdown potential (Eb) of Co-Cr alloy decreased in a concentration-dependent manner. hTe potential ranged for the breakdown of oxide film (Ev) was shortened in a concentration-dependent manner of NaCl. There was no obviousdifference in theIcorr of pure Ti with different concentrations of NaCl. hTe breakdown potential was not seen according to the polarization curves. Conclusion: In a certain range, the increase of the concentration of Cl- leads to accelerate the corrosion behavior of Co-Cr alloy, but it does not affect pure Ti.%目的：在模拟口腔环境下，探讨氯离子对钴铬合金和纯钛耐腐蚀性的影响。方法：通过对两种合金在不同NaCl(0.9%，2.0%，3.0%)浓度的中性人工唾液中进行电化学腐蚀指标测试并结合扫描电镜(SEM)扫描，观察其表面形貌。结果：钴铬合金和纯钛在三种人工唾液中的自腐蚀电位(Ecorr)的变化趋势无明显规律性，但是纯钛的自腐蚀电流密度(Icorr)明显小于钴铬合金。钴铬合金的自腐蚀电流密度随NaCl浓度的升高而增大，破裂电位值随NaCl浓度的升高而降低，氧化膜阳极破裂前的电位区间随NaCl浓度的升高而降低。纯钛的自腐蚀电流密度随NaCl浓度的升高基本无变化，并且所有纯钛试件的极化曲线均未出现破裂电位。结论：在一定范围内，氯离子浓度的升高会导致钴铬合金腐蚀加速，而对纯钛的耐腐性无明显影响。