AZ31镁合金表面聚吡咯的化学氧化合成及其耐蚀性能

以对甲苯磺酸钠为掺杂剂, 三氯化铁为氧化剂, 用化学氧化聚合法在AZ31 镁合金表面制备聚吡咯(PPy)膜. 采用傅里叶变换红外(FTIR)光谱分析了镁合金表面聚吡咯膜结构, 通过电化学极化曲线、电化学阻抗谱(EIS)研究了其耐蚀性能, 通过扫描电子显微镜(SEM)、X射线能量散射谱(EDS)分析了表面形貌和成分. 和镁合金裸样相比, 聚吡咯膜对镁合金腐蚀有一定的抑制作用. 硅烷预处理改善了镁合金/聚吡咯体系的耐腐蚀性能, 使腐蚀电位较镁合金裸样正移了110 mV, 电流密度减小了约2个数量级.

Chemical Oxidative Polymerization of Polypyrrole and Its Corrosion Resistance on the AZ31 Magnesium Alloy

Polypyrrole(PPy) was chemically synthesized from pyrrole using sodium p-toluenesulfonate as a doping agent and ferric chloride as an oxidant on the surface of the AZ31 magnesium alloy.Fourier transform infrared(FTIR) spectroscopy was used for structural characterization of the PPy film.The corrosion behavior of the PPy coated AZ31 Mg alloy was studied using an electrochemical polarization test and electrochemical impedance spectroscopy(EIS).Scanning electron microscope(SEM) and energy dispersive X-ray analysis(EDS) were used to observe the surface morphology and for elemental analysis of the film,respectively.The PPy film showed a certain corrosion inhibition on the AZ31 magnesium alloy.Silane pretreatment can improve the corrosion protection performance of the Mg/PPy system causing a positive shift of the corrosion potential by 110 mV and a decrease in the corrosion current density by two orders of magnitude compared with that of AZ31 Mg alloy.