Investigation of the Tribological Behavior and Microstructure of Plasma-Cladded Fe-Cr-Mo-Ni-B Coating

In this study, an Fe-Cr-Mo-Ni-B coating was prepared using plasma cladding on Cr5 steel substrate. The microstructure, phase evolution and tribological performance of the Fe-Cr-Mo-Ni-B coating were investigated. The microstructure is mainly composed of Mo₂FeB₂, Fe₂B, α-Fe, γ-Fe and MoB. The process of phase evolution in the coating was observed in situ by HT-CLSM. The Mo₂FeB₂ phase with good thermodynamic stability can exist in the high-temperature liquid phase. It also has a phenomenon of connection and merging and turns into different morphology during the plasma cladding process. The hardness value of coating was much higher than the base metal, and the hardness value of Mo₂FeB₂ (785.5 HV) was higher than the eutectic matrix (693.2 HV). The wear mechanisms of the cladding under dry sliding were primarily caused by adhesive wear, accompanying slight oxidation wear. The Mo₂FeB₂ phase has an important effect on the wear resistance property.