Microstructure and Wear and Corrosion Resistance of NiCrMo High-Entropy Alloy Coatings Modified with Fe-Based Amorphous Powders via Laser Cladding
Marine engineering components demand simultaneous wear and corrosion resistance, yet conventional NiCrMo high-entropy alloy (HEA) coatings produced by laser cladding exhibit insufficient hardness and passive film stability under tribocorrosion. This study introduces Fe-based amorphous powder (Fe77Si9B14) at 0, 10, and 20 wt.% into NiCrMo HEA coatings via laser cladding. Microstructural analysis reveals a transition from FCC/σ eutectic to FCC+σ with nanoscale Mo-rich precipitates. At 10 wt.% amorphous addition, hardness peaks at 1200 HV0.2 (1.3× the NiCrMo baseline), and the passive current density drops from 1 mA to 100 μA, an order-of-magnitude improvement. Dry sliding wear tests show a stable friction coefficient and a shift from severe spalling to smooth ploughing. Under wear-corrosion coupling, the 10 wt.% coating exhibits optimal passive film stability, with electrochemical response closest to an ideal capacitor. Excessive amorphous content (20 wt.%) increases FCC phase fraction and coarsens Mo-rich precipitates, reducing hardness to 723 HV0.2. The synergistic effect of σ-phase refinement and amorphous-derived nanostructure delivers superior wear and corrosion resistance, offering a viable route for extending the service life of marine components.