To enhance the operational damage resistance of hydraulic machinery, this study employed laser cladding technology to fabricate a Co_37.4Cr₃₀Ni₂₀Al₅Ti₅Nb_2.6 high-entropy alloy coating on 04Cr13Ni5Mo substrate. The influence of laser power on the microstructure and properties of the coating was systematically investigated. Based on preliminary research, the friction-wear performance and cavitation erosion behavior of the coatings prepared at 3000 W, 3200 W, and 3400 W were specifically examined. Results indicate that as the laser power increased from 3000 W to 3400 W, the microhardness of the coating gradually decreased from 345.3 HV_0.2. At 3000 W, the precipitation of trace strengthening phases significantly enhanced the mechanical properties. In wear tests under a 20 N load for 30 min, the wear rate of the coating prepared at 3000 W was 1.41 × 10⁻⁴ mm³/(N·m), which is 13.5% lower than that of the 3200 W coating (1.63 × 10⁻⁴ mm³/(N·m)) and 16.07% higher in wear resistance compared to the substrate. Cavitation erosion tests revealed that after 20 h of ultrasonic vibration, the mass loss of the 3000 W coating was only 2.35 mg, representing an 88.89% reduction compared to the substrate (21.15 mg), and significantly lower than that of the 3200 W (4.57 mg) and 3400 W (3.85 mg) coatings. This study demonstrates that precise control of laser power can effectively optimize the cavitation erosion resistance of high-entropy alloy coatings, providing technical support for their application in harsh environments.

Flow-passing components such as volutes and fixed guide vanes operating in high-velocity liquid flows with high sediment concentrations are subjected to long-term cavitation erosion and sand-particle abrasion, which cause substantial economic losses. To reduce the manufacturing and maintenance costs of mechanical equipment serving such environments, laser cladding was employed to fabricate Fe₄₅Cr₂₅Ni₂₀Ti₅Mo₅ multi-principal-element alloy coatings on Q235 steel substrate, and the effect of laser power on the microstructure and properties of the coatings was systematically investigated. On the basis of preliminary investigations, the present work elaborately analyzes the wear resistance and cavitation-erosion resistance of coatings fabricated under laser powers of 1000 W, 1200 W and 1400 W. The results reveal that the coating hardness gradually decreases from a maximum value of 485.67 HV_0.2 to 363.15 HV_0.2 with increasing laser power. When the laser power is 1200 W, the coating prepared under this laser power maintains a good balance between hardness and microstructural integrity. Under identical friction-and-wear test conditions, its wear rate reaches only 3.15 × 10⁻⁵ mm³/(N·m), which is reduced by 19.64%, 27.92% and 39.19% compared with the coatings produced at 1000 W, 1400 W and bare Q235 steel, respectively. After a 20h cavitation-erosion test, the mass loss of this coating is merely 2.56 mg, representing reductions of 72.88%, 81.5% and 96.91% relative to the 1000 W coating, 1400 W coating and Q235 steel substrate. The coating fabricated at 1200 W exhibits outstanding wear resistance and cavitation-erosion resistance. The results indicate that, under the experimental conditions of this study, the wear resistance and cavitation-erosion resistance of the coating can be effectively optimized by adjusting the laser power.