Investigations on microstructure and wear resistance of Fe-Mo alloy coating fabricated by plasma transferred arc cladding

A wear-resistant Fe-Mo alloy coating was fabricated on the AISI 1045 steel substrate by plasma transferred arc (PTA) cladding, using pure Mo powders as the precursor material. The microstructure, microhardness and wear resistance of the coating were investigated by scanning electron microscope (SEM) with energy dispersive spectrum (EDS), X-ray diffraction (XRD), Vickers hardness and pin-on-disk wear testers, respectively. It was found that the coating presented rapidly solidified microstructure mainly consisting of cellular R-Fe63Mo37 dendrites and a small amount of lamellar R-Fe63Mo37/α-Fess dendrites uniformly distributed in the α-Fess matrix. Based on the eutectic growth and undercooling theories, the possibility of the R/α peritectic coupled growth in the rapidly solidified peritectic Fe-Mo alloy was discussed. The extensive growth of columnar crystallites into the substrate provided good metallurgical bonding at the interface between the coating and the AISI 1045 steel substrate. The results showed that the microhardness and wear resistance of the coating were much higher than that of the AISI 1045 steel substrate. The transferred oxides layer containing MoO3 formed on the worn surface had a good friction-reducing property and also contributed to the wear resistance of the coating. [Display omitted] •A Fe-Mo alloy coating with high dilution was fabricated by PTA cladding.•Microstructure of the coating consists of fine dendrites uniformly distributed in the α-Fess matrix.•A large amount of ductile α-Fess phase in the coating provides fracture resistance during the wear process.•The transferred oxides layer containing MoO3 is formed during the friction process, which reduces friction coefficient.