Effect of Silane on Galvanic Corrosion between EW75 Magnesium Alloy and TC4 Alloy

摘要:

硅烷处理对镁合金具有良好的保护性。为了抑制 Mg-7Gd-5Y-Nd-Zr (EW75) 稀土镁合金和 Ti-6Al-4V (TC4) 钛合金的电偶腐蚀作用，以自腐蚀镁合金为对照组，对硅烷改性和未改性的镁合金与TC4钛合金的电偶腐蚀进行了研究。用数码照片和扫描电镜 (SEM) 观察分析了浸泡 48 h 后的镁合金表面形貌，样品的自腐蚀电流密度和电偶腐蚀电流密度分别用极化曲线和电偶腐蚀测量来表征获得。结果表明，硅烷膜可以减少失重比，使腐蚀形式由点腐蚀变为均匀腐蚀，因此硅烷改性的镁合金比未改性的镁合金具有更好的抗电偶腐蚀能力，其原因是硅烷膜可以提高镁合金的电位，并减小电偶腐蚀电流密度

Abstract:

Silane treatment has good corrosion resistance to protect magnesium. In order to delay the galvanic corrosion of Mg-7Gd-5Y-Nd-Zr rare earth magnesium alloy (EW75) and Ti-6Al-4V alloy (TC4), using self corrosion magnesium alloy as the contrast group, the galvanic corrosion behavior of magnesium alloy modified with and without silane coupled with TC4 alloy were investigated. The surface morphologies of magnesium alloy after immersion in NaCl solution for 48 h were examined with digital photography and scanning electron microscopy (SEM). And the self corrosion current density and the galvanic corrosion current density of the specimens were characterized by polarization and galvanic corrosion tests, respectively. The results show that silane film can reduce the weight loss rate of Mg alloy, and transform local pitting corrosion into uniform corrosion, and the magnesium alloy with silane pretreatment has better galvanic corrosion resistance compared with as-received Mg alloy. It can be explained that silane film can improve the potential of magnesium alloy and reduce the galvanic corrosion current density