Cavitation erosion/corrosion synergy and wear behaviors of nickel-based alloy coatings on 304 stainless steel prepared by cold metal transfer

Inconel 625 and Hastelloy C-276 nickel-based alloy coatings were prepared on 304 stainless steels by cold metal transfer (CMT), aiming at improving the resistance to corrosion, cavitation erosion and wear. The synergistic cavitation erosion-corrosion (SCE-C) effect of the coatings was also revealed in 3.5 wt% NaCl solution. Experimental results show that the Inconel 625 coating was composed of γ-phase matrix and MC-type carbide precipitates dominated by NbC, while the Hastelloy C-276 coating exhibited γ-phase matrix and Mo-rich p phase. Both corrosion resistance and cavitation erosion resistance of the Hastelloy C-276 coating and Inconel 625 coating were higher than that of 304 substrate, and the Hastelloy C-276 coating possessed higher corrosion resistance and cavitation erosion resistance than Inconel 625 coating as indicated by higher polarization resistance (152.95 kΩ cm2) and lower mean depth erosion rates (1.3 ± 0.15 μm/h). The carrier concentration ND of passivation film for Hastelloy C-276 coating (4.05 ± 0.01 × 1022 cm−3) was lower after 10h-cavitation erosion compared to Inconel 625 coating, indicating its passive film showing a stronger passivation behavior and protective ability. The Hastelloy C-276 coating also exhibited a higher wear resistance, and the wear mechanism was adhesive-abrasive comprehensive wear dominated by adhesive wear in the linear reciprocating wear test with Al2O3 as the friction pair. The wear resistance of Inconel 625 coating and Hastelloy C-276 coating was about 1.3 and 1.5 times that of 304 substrate, respectively. The Hastelloy C-276 coating fabricated in the present study exhibited a great potential as flow-passing parts in marine engineering fields due to the desirable resistance to corrosion, cavitation erosion and wear.