| Ceramics are priority applied for protective coating because of their excellent wear and corrosionresistance, heat resistance and high temperature oxidation resistance. However, ceramic coating showlow adhesion prepared by surface coating technique due to huge difference of Ceramic coatingmaterial and metal matrix material in physical performance. Ceramic coatings are easy to failure as aresult of huge thermal stress in the high temperature environment. In the paper, a fundamentalresearch on the high bonding strength ceramic coating prepared by laser cladding. A series of researchon the samples of MCrAlY/Al2O3-13ï¼…TiO2ceramic coating and microporous structure adhesivelayer/Al2O3-13ï¼…TiO2ceramic coating, which prepared by high frequency assisted laser cladding.Prepared for the ceramic coating, firstly, the sintering mechanism of the mechanism of ceramicmaterials under the action of laser was researched. Meanwhile, the model of laser was analyzed. Aresearch on the mechanism was carried out according to combination of experimental and theoreticalmethods. It can be divided into absorption, sintering, solidification three stages during ceramicmaterials sintering. According to the mechanism of sintering process, Al2O3-13ï¼…TiO2ceramic wereuse to experimental analysis. The result showed that, ceramic particle, shape, size and density have asuperior influence on the sintering properties of ceramic materials. Ceramic sintering was the mostsuperior performance when the size reaches the nanometer ceramic and spherical shape. Meanwhile,sintering properties of ceramic were increased significantly with the density of green body increases.While the temperature field of laser has a superior influence on sintering properties of ceramicmaterials. The thermal stress which induced microcrack will be reduced when the uniformtemperature field, and the separation was precipitated between the grains, but the size increased.A whole design scheme of high bonding strength was proposed according to the existingmechanism of high temperature ceramic coating failure analysis. It is designed MCrAlY/Al2O3-13ï¼…TiO2ceramic coating and microporous structure adhesive layer/Al2O3-13ï¼…TiO2ceramic coatingprepared based on idea of laser cladding. MCrAlY/Al2O3-13ï¼…TiO2ceramic coatings useconventional coating design. It is used MCrAlY bond layers reduce the differences of physicalproperties between the ceramic layer and matrix metal. Meanwhile, the feasibility verifying tests arecarried under different cladding conditions. The results showed that, ceramic coating can be preparedby high frequency assisted laser cladding pre-high density ceramic powder. A creative design whichproposed based on the needs of high-temperature work, it is microporous structure adhesive layer/Al2O3-13ï¼…TiO2ceramic coating. In the design, the adhesive layer is designed to be porousstructure, ceramic coating will has excellent high temperature properties result of microporousstructure has a high thermal shock resistance, low thermal expansion coefficient, can be used toreduce thermal stress of ceramic layer and matrix metal. Similarly, the feasibility verifying tests ofmicroporous structure sintering by laser are carried in order to prove scientific of the coating design.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) was applied to analyze thecomposition and microstructure of the MCrAlY/Al2O3-13ï¼…TiO2ceramic coating and microporousstructure adhesive layer/Al2O3-13ï¼…TiO2ceramic coating. The result showed that, MCrAlY/Al2O3-13ï¼…TiO2ceramic coating has a excellent chemical combination due to elements obviouslydiffused in the interface, will increase bonding strength of coating. In comparison with MCrAlY/Al2O3-13ï¼…TiO2ceramic coating, There is no obvious elements diffused in the interface ofmicroporous structure adhesive layer/Al2O3-13ï¼…TiO2ceramic coating result of the existence of alarge number of holes and changes in composition of adhesive layer. However, the interface is stilltightly under the action of microporous riveting.In order to estimate high temperature properties and failure mode of coating, bonding strength,high temperature oxidation and thermal shock of coating samples were tested respectively. The resultsshowed that MCrAlY/Al2O3-13ï¼…TiO2ceramic coating has good bonding strength and excellenthigh-temperature oxidation resistance, however,bonding strength of coating dramatically decreasedwith increasing thermal shock times. The microcracks are easily formed in the high temperature resultof huge thermal stress by residual stress test, add to use at low temperatures. Comparatively,microporous structure adhesive layer/Al2O3-13ï¼…TiO2ceramic coating had a slightly lower bondingstrength and excellent high-temperature oxidation resistance, but displayed a good thermal shockresistance. Final failure mode is thermal fatigue failure.Comprehensive result of work, a research on in-situ ceramic coating prepared by laser claddingwas carried out. MCrAlY/Al were used to in-situ about40mceramic coating prepared by lasercladding according to principle of Al in-situ oxidation. The result of study on microstructure showedthat in-situ ceramic coating and reaction layer combined closely to each other, meanwhile, there are alot of whiskers formed in the interface of the coating, the bonding strength will greatly increase,shows that the method is a very promising preparation of ceramic coatings.
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