Microstructure and Properties of Reactive Flame Sprayed Mo₂FeB₂ Cermet Coating

The powders for reactive thermal spraying (RTS) were synthesized by heat treatment at 900 ℃ for 2 h and crushed using Mo powders, FeB powders, Fe powders and Al powders as raw materials and PUB solution as binder. Cermet coatings were prepared by RTS on Q235 steel surface and heat treated at 1 000 ℃ under vacuum for 5 h. Microstructure and phases were investigated by XRD and SEM. The thermal shock resistance, wear resistance and corrosion resistance were tested. The results indicate that Mo2FeB2 and Fe3Al were generated in sinter-crushing powders after treated at 900 ℃. The coatings were composed of the hard phases of Mo2FeB2, Fe3Al and Fe-base binder phase, as well as oxides of Al2O3, B2O3 and MoO3. The thermal-shock times of the coatings without heat-treatment were 35, the wear resistance was 4.04 times higher than that of the substrate, the corrosion resistance in 4 wt% H2SO4 solution was 4.02 times higher. The thermal-shock times of the coatings were 55, the wear resistance and corrosion resistance were 7.36 and 6.13 times higher than those of the substrate after heat-treatment.