Effects of Al Addition on Microstructure and Wear Resistance of High-Velocity-Oxygen-Fuel-Sprayed FeCoNiCrMn High Entropy Alloy Coating

The spherical FeCoNiCrMn and FeCoNiCrMnAl_0.5 high entropy alloy powders were separately prepared by gas atomization. FeCoNiCrMn and FeCoNiCrMnAl_0.5 coatings were prepared by HVOF spray technique, respectively. BCC phase as a hard phase was observed in both of FeCoNiCrMnAl_0.5 powder and coating. Al addition is favor of oxidation resistance during spraying process and increasing coating microhardness from 341 HV_0.2 to 455 HV_0.2. Wear test was implemented under three different conditions with GCr15 balls (700 HV_0.2) as the counterpart. The results show that the coating with Al addition has high wear resistance and its wear rate is up to minimum value of 5.39 × 10^–4 mm³/Nm under the test condition with a load of 5 N and frequency of 5 Hz. The stable oxide layer is induced to effectively prevent the adhesive wear because of Al addition, which is promising method to improve wear resistance of FeCoNiCrMn coating.