Comparison of Different Cermet Coatings Sprayed on Magnesium Alloy by HVOF

In the present study, two different cermet coatings, WC-CrC-Ni and Cr₃C₂-NiCr, manufactured by the high-velocity oxy-fuel (HVOF) method were studied. They are labeled as follows: WC-CrC-Ni coating-WC and Cr₃C₂-NiCr coating-CrC. These coatings were deposited onto a magnesium alloy (AZ31) substrate. The goal of the study was to compare these two types of cermet coating, which were investigated in terms of microstructure features and selected mechanical properties, such as hardness, instrumented indentation, fracture toughness, and wear resistance. The results reveal that the WC content influenced the hardness and Young's modulus. The most noticeable effect of WC addition was observed for the wear resistance. WC coatings had a wear intensity value that was almost two times lower, equal to 6.5·10^-6 mm³/N·m, whereas for CrC ones it was equal to 12.6·10^-6 mm³/N·m. On the other hand, the WC coating exhibited a lower value of fracture toughness.