The effect of Ni201 transition layer on the corrosion, wear and synergetic cavitation erosion-corrosion behavior of CMT-Monel K500 coating

Abstract

The Monel K500 modified coating with Ni201 as the transition layer was prepared on the 304 stainless steel substrate by cold metal transfer (CMT) technology. Different from the Monel K500 coatings with direct deposition, the Ni201 transition layer can effectively block the diffusion of Fe and other elements in the substrate and avoid the deterioration of corrosion resistance of Monel K500 coating caused by galvanic corrosion in artificial seawater, which showed the highest polarization resistance and the strongest passivation tendency. In addition, the diffusion of Ni atoms in the transition layer compensated and stabilized the alloy element composition of the Monel K500 coating, making it have a finer microstructure and show higher microhardness and wear resistance. After 10 h- cavitation erosion (CE), the Monel K500 coating with transition layer showed the lowest mean depth erosion rates (MDER) of 2.2 ± 0.09 μm/h as it maintains the highest self-healing ability and integrity of passive film during the long-term synergistic effect of cavitation erosion and corrosion (SCEC). The introduce of the Ni201 transition layer can effectively improve the corrosion-cavitation and wear properties of CMT-Monel K500 surface modified coating, and then effectively prolong the service life of seawater overflow components such as butterfly valves, pump bodies, hydraulic turbines and heat exchangers, which has great application potential in the field of tribo-corrosion in ocean engineering.