Tribocorrosion behaviours and mechanisms of Inconel 625–nano/micro Al2O3 composite coatings prepared by plasma enhanced high-velocity arc spraying

Abstract

In the marine industry, non-skid coatings are applied to deck surfaces for properties like high friction, wear resistance, and corrosion protection. Previously, we had developed a plasma enhanced high-velocity arc spraying (PE-HAS) technique for preparation of high-quality Inconel 625–xAl₂O₃ composite coatings. In this study, the electrochemical and tribocorrosion properties of Inconel 625–nano/micro (n/m) Al₂O₃ composite non-skid coatings for large marine equipment were further investigated in a 3.5 wt% NaCl solution environment. The experimental results demonstrated that, the n-Al₂O₃ content significantly affected the porosity, electrochemical properties and passivation stability of the composite coatings. Notably, the best tribocorrosion performance was observed with 25 wt% n-Al₂O₃ content. In contrast to the Inconel 625 coating, the composite coating exhibited tribocorrosion mechanisms of adhesive wear and light abrasive wear. Additionally, typical corrosion behaviours, such as, pitting and intergranular corrosion, occurred primarily at the bonding interfaces between the heterogeneous phases. The enrichment of n-Al₂O₃ and the formation of in-situ corrosion products acted as barriers, impeding further solution penetration and thereby slowing the corrosion process. This study provides valuable theoretical insights for optimising the tribocorrosion properties of sprayed metal/ceramic composite non-skid coatings.