Production and characterization of novel Fe-based hard-face coating

Wear and corrosion phenomena are well known to reduce the lifetime of mining and agriculture equipment, where they are constantly subjected to abrasion and corrosive media. The hard-facing technique is used to improve the service life of such equipment, where the base material is coated with a high-wear and corrosion-resistant alloy. One of the methods used for hard-facing is the Laser-Based Directed Energy Deposition (DED/LB-M) process, where the coating alloy is deposited onto the liquified surface of the base material. Our work focuses on the production and characterization of a novel Fe-based alloy developed for hard-facing applications. The alloy was designed using high-throughput thermodynamic composition screening. The determined composition incorporates significant amounts of Mo, Cr, V, Ni, C, and B in order to ensure a martensitic matrix and a high fraction of hard boride and carbide phases, which can drastically enhance hardness and wear resistance of the coating. Furthermore, the high amounts of Cr and Mo can potentially improve corrosion resistance by forming a passive film and reducing the likelihood of localized corrosion. The raw material was synthesized using the VIGA process and subsequently deposited onto low alloy steel by employing the DED-LB/M process. Initially, optimized process parameters were devised to achieve a quality coating - characterized by minimal defects, low dilution, sufficient substrate bonding, and uniform thickness. Various characterization methods such as XRD, SEM, and EBSD were utilized to identify the microstructure of both powder and coatings. The presence of hard phases such as carbides and complex borides elevated the microhardness to 750–900 HV0.3. Furthermore, planned ASTM G65 wear abrasion tests and electrochemical corrosion assessments via potentiodynamic polarization will be conducted, and the results will be presented.