Studys On Microstructure And Properties OfAl₂O₃-40%TiO₂ Composite Ceramic Coatings By Atmospheric Plasma Spraying

Since ships’ long distance navigation in high temperature, high humidity and high salt fog of the marine environment, its key-important parts are vulnerable to damaging failure and producing larger damage area. The high precision is required for the process of repair. The normal sailing of ships are seriously affected. Therefore the repair and strengthening of surface of key-important parts are of great significance to the engineering practice.The Al2O3-40%Ti O2 ceramic coating was prepared by atmospheric plasma spraying technology. Its microstructure was observed. Microhardness, porosity, wear resistance, corrosion resistance, such as performance were tested. The spraying process parameters were optimized. The residual stress of coating in the cooling process was analyzed by the finite element method. And the surfaces of key-important parts were repaired and strengthened.(1) The microstructure, microhardness, porosity and wear resistance of the coating were analyzed by scanning electron microscope, microhardness meter, electronic balance,friction and wear testing machine, such as laboratory equipment.(2) The microhardness, porosity and fracture toughness of coating were comprehensive evaluated, based on four main parameters including spraying voltage,spraying current,main gas flow rate and spraying distance and range analysis method by orthogonal test method. The spraying process parameters of atmospheric plasma spraying Al2O3-40%Ti O2 ceramic coating were optimized. The effect of various factors on the quality of coating was analyzed.(3) The different spraying power samples were tested by electrochemical corrosion, full immersion corrosion and salt fog corrosion test. The polarization curve, corrosion quality were tested and the suface features of the salt fog corrosion were observed. The influence of spraying power on the corrosion resistance of plasma spraying Al2O3-40%Ti O2 coating was discussed. The corrosion mechanism of coating was analyzed.(4) The distribution of internal residual stress of coating during the cooling process was studied using the finite element method. The influence of the factors such as coating thickness, porosity, and crack on the residual stress was discussed.(5) According to the actual situation of key-important parts failure, parts were repaired and strengthened using plasma spraying which the Al2O3-40%Ti O2 coating was prepared by. The wear resistance and corrosion resistance of key-important parts are enhanced. The service life is improved and cost savings. The contents of green maintenance and remanufacturing are enriched.