Y2O3stabilized ZrO2(YSZ)thermal barrier coatings on high-temperature alloywere prepared by air plasma spraying technology.The surface coatings arerespectively micro-YSZ coating and nano-YSZ coating.The bond coating isNiCoCrAlY.Based on the results of the experiments of high temperatureoxidation,hot orrosion and thermal shock,the effect of the phase and themicrostructure of YSZ coatings on their performance by using the X-ray diffraction（XRD）,standard electronic modules(SEM) and energy ispersive spectrometry（EDX）.
The results show that there are thermally grown oxide(TGO),the maincomponents of which is lumina,between bond coatings and surface coatings after high temperature oxidation.The micro-YSZ coatings have the higher oxidation rates than the nano-YSZ coatings.The high temperature oxidation resistance of nano-YSZcoatings are better.
The formation of monoclinic ZrO2and YVO4crystals as hot corrosion products caused the degradation of YSZ coatings.The reactions of the hot corrosion and the transformation of tetragonal zirconia to monoclinic phase supplement each other.Compared with the micro-YSZ coating,the nano-YSZ coating has superior hotcorrosion resistance.
The life of nano-YSZ coatings is twice as long as the life of micro-YSZ coatings.The degradation eason of the coatings are mainly two:first of all,the expansion factor of the alloy and the surface coatings does not match,which leads to the degradation due to the residual stress it makes.Secondly,Oxygen through the cracks and matrix reacts with the alloy and the bond coatings.The formation of the oxide leads to the degradation due to the residual stress it makes.
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