Fabrication and Properties of APS- and RTS-Sprayed TiB_2/Mo_2FeB_2 Multiphase Ceramic Coating on Q235 Steel

摘要

A kind of TiB_2/Mo_2FeB_2 composite powders for reactive thermal spraying (RTS) and atmospheric plasma spraying (APS) were prepared using Mo powder, Fe-B alloy powder, Fe powder and TiB_2 powder. The TiB_2/Mo2FeB_2 composite ceramic coatings were synthesized and deposited by APS and RTS on Q235 steel. Microstructure and phases were investigated by X-ray diffraction (XRD) and scanning electrical microscopy (SEM). The thermal shock resistance, wear resistance and corrosion resistance were characterized with the relevant lab testing equipment. The result indicates that the coatings are composed of the major phases Mo_2FeB_2, TiB_2 and α-Fe, a little of Fe_2O_3, FeO, and B_2O_3.The thermal-shock times of RTS-sprayed coatings is 44, the corrosion resistance is 6.07 times than those of the substrate, respectively, while those of APS-sprayed coatings are 55 and 15.5, respectively. The mass loss of Q235 steel is 138.6g/m~2, while the mass loss of the coatings with 30% TiB_2 which were prepared by RTS is 28.0952g/m~2, the mass loss of the coatings with 30% which were prepared by APS is 15.4028g/m~2, when the testing load was 400N. Therefore, the coatings with 30%TiB_2 prepared by APS possess better wear resistance than the Q235 steel substrate.