Tribocorrosion Properties of NiCrAlY Coating in Different Corrosive Environments

Atmospheric plasma spraying (APS) was taken to fabricate the NiCrAlY coating. The corrosion-wear properties of NiCrAlY coating was measured respectively under deionized water, artificial seawater, NaOH solution and HCl solution. Experimental results presented that the as-sprayed NiCrAlY coating consisted of Ni₃Al, nickel-based solid solution, NiAl and Y₂O₃. In deionized water, the coating with the lowest corrosion current density (i_corr) of 7.865 × 10^-8 A/cm² was hard to erode. Meanwhile, it presented a lower friction coefficient and the lowest wear rate. In HCl solution, NiCrAlY coating gave the highest corrosion current density (i_corr) of 3.356 × 10^-6 A/cm² and a higher wear rate of 6.36 × 10^-6 mm³/Nm. Meanwhile, the emergence of Al(OH)₃ on the coating surface could reduce the direct contact between the counter ball and sample effectively, which was conducive to the lowest friction coefficient of 0.24.