Comparison of Structure and Properties of Mo₂FeB₂-Based Cermets Prepared by Welding Metallurgy and Vacuum Sintering

At present, most Mo₂FeB₂-based cermets are prepared by vacuum sintering. However, vacuum sintering is only suitable for ordinary cylinder and cuboid workpieces, and it is difficult to apply to large curved surface and large size workpieces. Therefore, in order to improve the flexibility of preparing Mo₂FeB₂ cermet, a flux cored wire with 70% filling rate, 304 stainless steel, 60 wt.% Mo powder and 40 wt.% FeB powder was prepared. Mo₂FeB₂ cermet was prepared by an arc cladding welding metallurgy method with flux cored wire. In this paper, the microstructure, phase evolution, hardness, wear resistance and corrosion resistance of Mo₂FeB₂ cermets prepared by the vacuum sintering (VM-Mo₂FeB₂) and arc cladding welding metallurgy method (WM-Mo₂FeB₂) were systematically studied. The results show that VM-Mo₂FeB₂ is composed of Mo₂FeB₂ and γ-CrFeNi.WM-Mo₂FeB₂ is composed of Mo₂FeB₂, NiCrFe, MoCrFe and Cr₂B₃. The volume fraction of hard phase in WM-Mo₂FeB₂ is lower than that of VM-Mo₂FeB₂, and its hardness and corrosion resistance are also slightly lower than that of VM-Mo₂FeB₂, but there are obvious pores in the microstructure of VM-Mo₂FeB₂, which affects its properties. The results show that WM-Mo₂FeB₂ has good diffusion and metallurgical bonding with the matrix and has no obvious pores. The microstructure is compact and the wear resistance is better than that of VM-Mo₂FeB₂.