The Preparing Of Al₂O₃-MxOy Composites Coating And The Applying Research Of Phosphor Chemistry

The preparing of Al2O3-MxOy hard-faced ceramic composites had been carried out by means of plasma thermal spraying and the poly-oxides ceramic coating was prepared on the substrate by means of coating and sintering method. The phase structure,phase compositions,micro-structure characteristic and elements distribution of the Al203-MxOy hard-faced ceramic coating were analyzed by using large-field optical microscope and X-ray diffraction and electric probe . The small experiments simulated the producing conditions of phosphor chemistry and the small samples in the laboratory were analyzed .Two middle-scale materials were prepared by using the plasma spraying weld method and the coating and sinering method. Furthermore, the vanes of phosphor chemistry blender prepared by these two methods were applied to the producing of phosphor chemistry in order to improve the wear resistance and corrosion resistance properties of phosphor chemistry equipments.The test of these small samples revealed: there are clear interfaces between the metal substrate, the previous coating, the transitional coating and the final coating, the coating characterized by layer structure that was composed by countless anamorphic grains and holes. The test from X-rays diffraction revealed that the phases of ceramics coating were composed by the solid solution B-Al2O3.TiO2,meta-stable Y- Al2O3,stable a-A12O3 and TiO2.Because of using the previous coating and transional coating, the properties differences between metals and ceramics were reduced and the bonding strength was improved and the residual stress in the coating was reduced. The ceramic coating had better plasma thermally sprayed properties when other ceramic powder (for example:TiO2,Si02,B203, Na20, MgO) were mixed in the A1203. Besides the ceramic coating possessed higher compactness, hardness, bonding strength and better wear resistance and corrosion resistance than the substrate (A3 steel) . Furthermore, because of the scanning remelting the coating after spraying, there were firm metallurgy bond that increased the bonding strength and reduced the numbers of holeand increased the wear resistance and the corrosion resistance of ceramic coating.In conclusion, the quality of the ceramic coating prepared by means of the plasma sprayed weld method was related to many factors , including coating design ,spraying equipment, spraying technics parameter, the propertiers of ceramic powder and bonding mechanism between the ceramic coating and the metal substrate.