Slurry erosion behaviour of AlCoCrFeNi high entropy alloy coating prepared by atmospheric plasma spraying

This study explores the application of AlCoCrFeNi high entropy alloy (HEA) coating on the SS316L steel using atmospheric plasma spraying to enhance durability in erosive environments. Annealing the coated sample at 650°C resulted in a uniform, dense coating with homogeneous HEA distribution, exhibiting a 16.2% improvement in microhardness compared to the pre-annealed coating. Slurry jet erosion testing revealed that under specific conditions (10 m s−1 impact velocity, 90° impingement angle and 10 wt-% slurry concentration), the annealed coating demonstrated a lower erosion rate. Increased velocity correlated with higher erosion rates due to augmented material removal, while normal angles exhibited lower erosion rates than oblique angles, emphasising plastic deformation over material removal. Initial erosion rate increases with slurry concentration were observed, followed by a decrease due to the protective effect of a slurry cloud at higher concentrations. Overall, the HEA-coated layer effectively safeguarded against erosive wear, particularly post-annealing, because of enhanced hardness.