Effect of sintering temperature on the microstructure and performance of a ceramic coating obtained by the slurry method

In this paper, SiO2, Cr2O3, Al2O3, and MgO were used as ceramic aggregates, and a small amount of Al powder was added. A ceramic coating was prepared on a Q235 steel substrate. The effect of the sintering temperature on the coating microstructure, phase structure and wear resistance was studied by Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and friction and wear testing. The results show that the tensile strength of the ceramic coating is increased after sintering, the structure becomes dense, and the size of coated micropores is increased to release the internal tensile stress. With the increase of the sintering temperature and tensile stress, the micropores begin to release the excess tensile stress in the form of crack initiation and expansion. The mineralization of MgO, Cr2O3, nMgO and mSiO2 phases can be achieved by sintering the coating at 200 °C; the oxygen in the atmosphere migrates along the micropores in the coating to react with Fe in the steel substrate, forming FeO, and the resulting FeO reacts with the SiO2 in the coating to form the Fe2SiO4 phase. The coating has the best wear resistance after being sintered at 400 °C, and the abrasion resistance of the sample is 6.7 times higher than that of the sample dried at room temperature.