Study On Integrated Performance And Design Of The Infrared Low Emissivity Multilayer Composite Coatings With High Temperature Resistance

The application of infrared low emissivity coatings with high temperature resistant is mainly aimed at the aircraft engine hot-section components,which can effectively measure to shorten the identified distance and reduce the infrared radiation.Presently,the ceria-based coatings have good infrared low emissivity or good thermal shock resistance with different formulas,which can not meet the low infrared emissivity and high thermal shock resistance at a singal coating.Therefore,the multi-layer coatings structure to achieve infrared low emissivity and high thermal shock compatibility is explored to improve the comprehensive performance.At the same time,we optimize the related methods to enhance the emissivity of the coating and thermal shock resistance.The obtained research results are as follows:1.The CeO₂ co-doped with Y³⁺ and Ca²⁺ can signif icantly reduce the infrared emissivity emissivity with the method of co-precipitation.The powder of(Ce_0.8Y_0.15Ca_0.05O₂-?)has the lowest infarared emissivity value of 0.241 when doping amount of Y³⁺ and Ca²⁺ is 15% and 5% respectively.At the same time,which irradiation treated by 50 KGy 60Co gamma ray can induce the infrared emissivity of the powder Ce_0.8Y_0.15Ca_0.05O₂-?,and the infrared emissivity of treated powder reach the lowest value 0.147 when the test temperature is 700°C.The filler of the surface coating was prepared by the above chemical and physical modified methods.The infrared emissivity of the surface coating has the lowest value 0.282 with the test temperature is 600°C.2.CeO₂ co-doped with La³⁺ and Mg²⁺ can improve the thermal expansion coefficient of the binding coating.Thereby,it can reduce the thermal expansion coefficients between the multi-layer coatings and the substrate with the co-doped powders and improve the thermal shock resistance of multi-layer coatings.3.Orthogonal test has been applied to study the optimal parameters of the spray coating with the scheme.And to optimize the process parameters of coating viscosity,spray pressure and spray angle.Furthermore,it reduces the impact from preparation process on the performance of the coatings.4.The multi-layer coatings have been prepared according to the design of surface layer,bingding layer and transition layer combined with the multilayer structure.We test comprehensive performance,the lowest infrared eimissivity and the thermal shock up of which is 0.284 and 51 times respectively.Above all,it has a good performance of heat resistance and oxidation resistance at high temperature...