The Process Optimization Of Ceramic Coating By Supersonic Atmosphere Plasma Spraying And The Research On Wear-resisting Performance

Abstract:Cr2O3and thermal sprayed A12O3coating has been one of the most widely used as wear-resistant, corrosion resistant coating. Owing to its excellent properties such as high temperature stability,high hardness, excellent wear resistance, corrosion resistant and heat resistant, low friction coefficient. However, The wear is one of the important factors leading the coating failure in practice. Therefore, studies into the preparation process,friction and wear perpormance of Cr2O3coating and Al2O3-3%TiO2(AT3)coating have great significance to the coatings. In this article, Cr2O3coating and Al2O3-3%TiO2coating are prepared by supersonic plasma spraying(SAPS) equipment imported from Ukraine. Throughing the wheel to grind grain abrasion test, combined with the scanning electron microscope (SEM), X-ray diffraction (XRD), electron energy spectrum (EDS)and other means, Then studing and analyzing the microstructure, friction and wear performance and the coating surface before and after the wearing of Cr2O3coating and Al2O3-3%TiO2coating.At the same time, preparing by supersonic atmospheric plasma spraying(APS), And then comparing and analysing the microscopic morphology of Cr2O3coating and Al2O3-3%TiO2coating. The results are as follows:SAPS equipment with higher power, can melt particles at high temperature in a short time, So the coating surface has certain amorphous. There is a difference between original powder and coating surface on XRD phase:mainly for diffraction peak width, the decrease of diffraction intensity;The influence of process parameters on the hardness of Cr2O3coating primary and secondary order:air pressure to spray current, spraying distance. The optimizing parameter:spraying current is270A, air pressure is0.40MPa, spraying distance is200mm, Applying SAPS under this process parameter can prepare relative density, small pore and uniform Cr2O3coatings.The coating possesses a micro-hardness of2067HV0.3; Air pressure and current has a great influence on microstructure of Cr2O3coating, Cr2O3coating occurs porous micro cracks frequently if current too high, powder reunion and nonuniform coating preparaed in low current;The parameters impacting AT3coating hardness and wear-resisting are the same:spray current to spraying distance and air pressure. The optimizing parameter:spraying current is330A, air pressure is0.35MPa, spraying distance is170mm, The coating under this parameters is compact, uniform, small pore, the micro hardness is1238HV0.3;Comparing with APS, SAPS preparaing Cr2O3and AT3coating which are uniform and have the structure of composition, small porosity, little and short micro cracks, coating molten state is good. The microstructure of the coating is improved further, obtaining better wear resistance. Both two ceramic coating are characterized by abrasive wear and brittle fracture. The wear resistance of Cr2O3coating prepared by SAPS is about2-4times than APS. The wear resistance of AT3coating prepared by SAPS is about2-3times than APS.