Significant improvement of corrosion resistance in laser cladded Zr-based metallic glass matrix composite coatings by laser remelting

The corrosion behaviors and underlying mechanisms of laser remelted Zr-Cu-Ni-Al metallic glass matrix composite coatings (MGMCCs) were investigated systematically. The remelted coatings exhibit significantly enhanced corrosion resistance with the lowest corrosion current density of 3.96×10−9 A/cm2 among the reported Zr-Cu-Ni-Al metallic glass (MG) alloy and coatings in 3.5 wt% NaCl solution. The passive film is mainly constituted by ZrO2and Al2O3, and its formation follows the point defect model. Corrosion was preferentially initiated at the crystalline/amorphous interface. By increasing the MG content and suppress the formation of Cu-rich crystalline phase, the corrosion resistance of Zr-Cu-Ni-Al MGMCC can be improved.