LAUSR

Combining a technology of a composite coating and a new development idea of a functionally gradient deposits, a kind of novel gradient nickel–tungsten–zirconium dioxide (Ni–W–ZrO2) composite coating was successfully prepared on LY12 alloy substrate by using concentration of sodium tungstate varying as 20 g/L, 50 g/L, 80 g/L, 120 g/L, 160 g/L, and 200 g/L in the bath. The results showed that the W content of as-deposited gradient Ni–W–ZrO2 composite coating was gradually increased to 50.50 wt% along the coating growth direction, its structure transitioned from amorphous to crystal line, and the tungsten nickel (Ni4W) phase was precipitated after heat treatment at 400 °C for 1 h. In addition, the wear and oxidation resistance, and anti-corrosion of gradient Ni–W–ZrO2 composite coating were generally enhanced with increase in heat treatment temperature. Moreover, the wear resistance, oxidation and corrosion resistance of gradient Ni–W–ZrO2 composite coating achieved optimal values after heat treatment at 400 °C for 1 h for the gradient structure and high W content.