动电位极化技术在口腔修复材料腐蚀测定中的应用

Applications of potentiodynamic polarization technique in corrosion behavior measur ements of prosthodontic alloys

目的 探讨动电位极化技术在体外测定口腔修复金属材料腐蚀中的应用、可重复性、可比性和可信性。方法 将 5种具有代表性的口腔修复金属材料分别置于人工唾液 ,从 -2 5 0mV(相对于自腐蚀电位 )至 12 0 0mV(相对于参比电极 )的电位对样本进行阳极极化扫描 ,并对经极化处理的样本表面进行金相显微镜观察。结果 同种材料间的极化曲线具有较好的可重复性 ,而在某些不同材料间有明显差别。特征性参数 :自腐蚀电位、初始稳态钝化电位、维钝电流密度和过钝化电位便于统计学分析 ,再参照极化曲线的叠加图可以综合评价修复材料的表面稳定性、钝态范围和孔蚀的敏感性 ,并且在总体上与金相显微镜所观察一致。结论 此方法对在体外评价修复金属的腐蚀性是合适的。

Objective To study the application of the potentiodynamic polarization technique, and its reproducibility, comparability and reliability in testing the corrosion behavior of prosthodontic alloys in vitro . Methods A total of 5 different alloys were subjected to anodic polarization scan within the potential range from -250 mV (Ecorr) to 1 200 mV (SCE) in the artificial saliva and the surfaces of the specimens were examined with metallurgical microscopy. Results The polarization curves showed fair reproducibility in the same alloy, but great differences among different alloys. The parameters such as corrosion potential, passive potential, passive current density and transpassive potential were obtained and subjected to statistical analysis. All this parameters and superposition curves of different alloys were used to evaluate the surface stability, passive range and sensitivity to pitting corrosion, which were identical with the results from metallurgical microscopy. Conclusion The potentiodynamic polarization technique can be applied as an in vitro corrosion measurment for prosthodontic alloys.