Corrosion resistance multi-functional chemical conversion coating on Mg-Gd-Y-Zr alloy with high absorbance and electrical conductivity

Abstract

In this work, a new design of phosphate chemical conversion coating with low electrical contact resistance and high light absorption (C-E-PCC) on Mg-Gd-Y-Zr (Mg-RE) alloy was proposed. The conversion coating was stained with black dye aiming to blacken PCC, and post-treated with silane loaded nano-Ag wire, achieving low electrical contact resistance (ECR) due to the overlapping network of Ag wires on the surface of PCC. The experimental results indicated that the hydrogen evolition volume of C-E-PCC was 2.54 ± 0.09 ml/cm2 immersion 3.5 % wt NaCl for 120 h. The absorption in the visible light range of C-E-PCC was 30%. Moreover, the ECR of C-E-PCC was 11.00 ± 0.47 Ω. The aforementioned results implied that the PCC not only with high absorbance and low ECR but also with high corrosion protection.