Effects of WC on the cavitation erosion resistance of FeCoCrNiB0.2 high entropy alloy coating prepared by laser cladding

Abstract

To improving the cavitation erosion resistance (Re) of the FeCoCrNiB0.2 high entropy alloy (HEA), the FeCoCrNiB0.2 + WC (0 wt.%, 20 wt.%) HEA coatings were synthesized with premixed high-purity on Q235 steel by laser cladding (LC). The effects of WC on the hardness and Re were investigated. The cavitation erosion (CE) behavior in distilled water and 3.5 wt.% NaCl solution and microhardness were evaluated using an ultrasonic vibrator and Microscopy/Vickers hardness tester. The cavitation mass loss and surface morphology were used to characterize the cavitation damage. Experimental results showed that the Vickers hardness of FeCoCrNiB0.2 + 20 wt.% WC coating was higher than that of FeCoCrNiB0.2 coating, and the cumulative mass loss of FeCoCrNiB0.2 + 20 w.t% WC coating was less than that of FeCoCrNiB0.2 coating. The presence of chloride ion interacts with CE, forming a combined cavitation-corrosion damage, which accelerates the removal of material from the surface. Adding 20 wt.% WC, the number of cavitation pits was significantly reduced and the depth of pits also became shallower, which means that the addition of WC could weaken the degree of cavitation damage.