盐水介质中 Ti12Mo5Ta合金的电化学特性

摘要

The electrochemical behaviours of unrecrystallized and recrystallized Ti12Mo5Ta alloys were compared with those of the unrecrystallized Ti12Mo alloy and commercial pure titanium (cp-Ti). Experiments were carried out using physiological 0.9%NaCl solution (pH 2.3) at 37 °C. Very low passive current densities (in order of 10−6 A/cm2) were obtained from the anodic polarization curves, indicating high resistances of all samples in acidified 0.9% NaCl solution. Scanning electron microscopy (SEM) was employed to observe the surface morphology and all sample surfaces were identically corroded, no pitting, cracks, or other defects appeared on the sample surfaces after anodic potentiodynamic polarization tests. Equivalent circuit was used for modeling the electrochemical impedance spectroscopy (EIS) data, in order to characterize the sample surface and better understand the effect of Mo and Ta addition on the cp-Ti and the effect of recrystallization. The EIS results confirm that all titanium samples exhibit passivity in physiological 0.9%NaCl solution (pH 2.3) at open circuit potential (polarization resistance is around 105Ω·cm2). The corrosion resistance of these samples in physiological 0.9% NaCl solution (pH 2.3) at 37 °C is in the following order of recrystallized Ti12Mo5Ta>unrecrystallized Ti12Mo5Ta>unrecrystallized Ti12Mo>cp-Ti.%比较了未再结晶和再结晶Ti12Mo5Ta合金、未再结晶Ti12Mo合金和工业用纯钛(cp-Ti)在0.9%生理盐水(pH 2.3)中37°C下的电化学行为。从阳极极化曲线中得到了极低的钝化电流密度(10−6 A/cm2)，这表明所有样品在酸性0.9% NaCl溶液中具有高的耐蚀性能。采用扫描电子显微镜(SEM)观察样品的表面形貌，发现所有样品表面受到了相同的腐蚀，而且经阳极动电位极化测试后的样品表面没有出现点蚀、裂纹或其它缺陷。使用等效电路模拟电化学阻抗谱(EIS)数据，以表征样品表面且更好地理解Mo和Ta的添加对cp-Ti及再结晶的影响。EIS结果证实，在开路电位下，所有样品在0.9%NaCl溶液(pH 2.3)中产生钝化(极化电阻约为105Ω∙cm2)。在37°C时，样品在0.9% NaCl 溶液中(pH 2.3)的耐蚀性顺序为：再结晶 Ti12Mo5Ta>未再结晶 Ti12Mo5Ta>未再结晶Ti12Mo>cp-Ti。