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

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.