Research Of Properties And Preparation Technology Of Multiphase Ceramic Coating With Reactive Flame Spraying Process On AZ31B

In this study, Al₂O₃/TiO₂ multiphase ceramic coating was prepared on the surface of AZ31B magnesium alloys by the ordinary thermal spraying and SHS thermal spraying. Resarch of micro-morphology, element distribution, phase composition and other microscopic features of the Al₂O₃/TiO₂ multiphase creamic coating on AZ31B by SEM, XRD, EDAX and other methods. Analyze of the effects of coating's components and performance with the change of the proportion of Al to CuO in thermite and thermite to ceramic aggregate. Test of the micro-hardness, bonding strength, thermal shock resistance performance, wear resistance, corrosion resistance and other performances of the Al₂O₃/TiO₂ multiphase creamic coating on AZ31B.The results show that: the best ratio of spray powder is that Al to CuO in thermite and thermite to ceramic aggregate are 3:1 and 1:1. SHS reaction ceramic coating has metallurgical bonding, elements distributed uniform and Cu4MgO5, CuAlO₂ and so on we found by X-ray. Porosity of SHS reaction ceramic coating is 15.15%, which decreased to 0 by sealing of hole. Microhardness and bonding strength aggregate are 998.78HV and 7.72MPa of SHS reaction ceramic coating. Thermal shock times respectively can reach 40 and 30 in 400℃and 500℃. The tests of abrasive wear resistance, adhesion dry-abrasion resistance and adhesion oil-abrasion resistance show that wearing resistance of SHS reaction ceramic coating was respectively 6.48, 3.32 and 6.04 times of the substrate's. Corrosion resistance of the SHS reaction ceramic is 5% acetic acid and 3.5% NaCl solution is respectively 24.37 and 7.15 times of the substrate's.Two methods of thermal spray coating system in the comparison found: preparation of the SHS-sprayed ceramic coatings in the micro-hardness, bonding strength, porosity and other mechanical and physical characters are superior ordinary thermal spraying of the ceramic coating.