Sustainable WC-FeCrNiMo coatings by high-velocity air fuel technique: Corrosion and tribocorrosion performance compared to standard WC-CoCr system

This study explores the corrosion and tribocorrosion behaviour of sustainable WC-FeCrNiMo coatings that use a Co-free binder, deposited via high-velocity air fuel (HVAF) process, and compared with standard WC-CoCr coatings. The effects of powder particle size and binder chemistry were systematically evaluated. All coatings displayed dense microstructures that maintained feedstock features, with higher deposition efficiency observed for coarser powders. XRD analysis showed minimal phase changes, with only slight decarburization. Electrochemical testing indicated that coatings made with fine WC-FeCrNiMo powder had better corrosion resistance, characterized by lower passivation current density (I pp ), a well-defined passivation plateau, and higher impedance. Tribocorrosion tests at both open circuit potential (OCP) and potentiostatic conditions showed stable electrochemical responses and a similar wear rate for coating deposited with fine WC-FeCrNiMo powder. Overall, HVAF-sprayed WC-FeCrNiMo coatings, especially with fine powder feedstock, offer a promising, sustainable alternative to traditional Co-based WC coatings in applications requiring corrosion and wear resistance. • Fine WC-FeCrNiMo coating shows a well-distinctive passivation plateau resulting in enhanced corrosion resistance. • Fine WC-FeCrNiMo coatings reveal stable electrochemical response in tribocorrosion conditions. • Fine WC-FeCrNiMo coatings possess comparable volume loss compared to WC-CoCr coatings. • Co-free WC-FeCrNiMo offers a sustainable alternative for corrosion–wear applications.