On the Applicability of Iron-Based Coatings Against Abrasion and Cavitation Erosion Wear

Iron-based coatings are often considered as replacement of hard chromium and WC-Co, as they pose lower health and environmental impact. In many cases, the combination of mechanical and chemical properties of iron-based alloys may be satisfactory and their relatively low cost makes these coatings an interesting candidate for many applications. This study is inspired by opportunities to harden the iron-base materials by strain hardening, solid solution strengthening, and precipitation hardening. Already commercially available Fe-based coating materials with precipitates of mixed carbides and borides in the metastable austenitic matrix achieve a high hardness. In this study, the cavitation erosion and abrasion resistance of various Fe-based coatings produced by HVAF and HVOF processes were investigated. Four experimental precipitates containing materials were prepared, and the sprayed coatings were tested for abrasive wear and cavitation erosion. In addition to precipitates, the contributions of martensite and retained austenite phases were investigated by influencing the microstructure through heat treatments, as the ability of these phases to influence ductility and toughness can be crucial to achieve the desired material properties. The properties of experimental and two commercial Fe-based alloys are compared with WC-Co and Cr₃C₂-NiCr coatings by property mapping.