Study Of Preparation And Propertities Of Micro/Nano-Composite Y-PSZ Reference-Phase Based High-temperature Seal Coating

The performance of the aeroengine is put forward higher requirement with the rapid development of aerospace industry. The new type seal coating system applications in high temperature is one of the important ways, which can improve the industrial efficiency of aeroengine and prolong the service life of aeroengine. The paper described several mainstream sealed technology currently, especially abradable seal technology and application. The performance of several component materials and development status of seal coating materials is introduced.For the seal coating used had the special nature of performance requirements, in this paper, The material powder compound by micro/nano-composite Y-PSZ matrix, nano-Al2O3for binding phase, tender material h-BN in high temperature and the pore-forming mechanism of component was prepared for the abradable seal coating. Then the nano Y-PSZ, micro Y-PSZ and micro/nano-composite Y-PSZ based five seal coating was prepared by air plasma spraying (APS) process. The seal coating materials, the microstructures of the seal coating and performance were analyzed and discussed.The results show that:(1) The reunion of spray-powder had hollow and round ball structure、 outstanding density and mobility and powder materials in the distribution of uniform components. The seal coating materials was prepared for the coating, the base-phase ZrO2existed in tetragonal and cubic structure styles and the other component materials had not phase transformation.(2) The five types of the deposition efficiency of the coating material are test comparatively and analysised. The more content of micron ZrO2, the higher deposition efficiency of the coating material, so the entire spraying process is more efficient and continuity.(3) The nano Y-PSZ based seal coating existed in smooth lamellar cellular style of structure, fairly loose and the porosity is too large.The micro Y-PSZ based seal coating existed large areas of block structure, more densely and the porosity of coating is scarce and most irregular multi-cusp type. But the micro/nano-composite Y-PSZ based seal coating were formed together by special two areas, one was completely melt by crystalline area (I area), the other was not completely melt deposition area (II area). The pore distribution and structure of seal coating was more reasonable, the performance of seal coating was well.(4) The superficial Rockwell hardness and bond strength of the three seal coating were test. The out of standard hardness range of1#and2#coating was too wide, but suitable standard hardness of the coating wide range of thickness was prepared for the micro/nano-composite Y-PSZ based seal coating, and it can ensure the abradable performance of the seal coating. Three different materials seal coating in coating thickness of2.5mm, the bond strength of the seal coating was very high.(5)The thermal shock performance of the seal coating was satisfyied basically with the seal coating requirement. The mismatch of the thermal expansion coefficient of the ceramic material and metal bond bottom layer material and TGO (thermally grown oxide) generated in high-temperature environment is the main reason for thermal shock failure of the abradable seal coating system.