Preparation Of Yttrium Titanate Coating And Its High Temperature Infrared Spectral Characteristics

Multi-frequency and omnidirectional stealth technology of aircraft is the focus of research in recent years.In order to solve the problem that traditional metal materials cannot be used at high temperature for a long time and cannot take into account multiple stealth requirements.In this thesis,Y₂Ti₂O₇pyrochlore structure ceramic material with low emissivity,low dielectric constant and high temperature stability is taken as the research object.The process characteristics of the material are studied by atmospheric plasma spraying technology.The infrared radiation characteristics are regulated by Zr⁴⁺doping,and the high temperature application performance is systematically studied.The main contents and conclusions are as follows:（1）In this thesis,Y₂Ti₂O₇coating was prepared by atmospheric plasma spraying and its infrared radiation properties were analyzed.The results show that the improvement of coating structure,the increase of density and the decrease of porosity caused by the increase of characteristic spraying parameters（CPSP）are the main reasons for the increase of infrared emissivity of the coating.When the CPSP value is the smallest,the coating porosity is the largest,and the infrared emissivity is 0.53.（2）The YZTO coating was successfully prepared on the surface of the metal substrate by doping the Y₂Ti₂O₇material with the same group of Zr atoms that can replace Ti atoms.The coating can further regulate the infrared radiation characteristics,and with the increase of Zr⁴⁺doping content,the crystal structure will change from the ordered pyrochlore structure to the defective fluorite structure,and the oxygen vacancies caused by Zr-Ti increase,which makes the infrared emissivity decrease significantly.（3）The performance of the doped YZTO coating at high temperature was analyzed.The experimental results show that the long-term high temperature environment enables the coating to undergo further crystallization.The volume shrinkage caused by crystallization will bring pores and cracks to the coating,which further reduces the infrared emissivity of the coating.In this thesis,aiming at the urgent need of research and development of low infrared radiation characteristics of high temperature components,the influence of crystal structure and microstructure of materials on infrared radiation characteristics is analyzed in detail by means of new coating preparation.The infrared radiation characteristics of the material were regulated by optimizing the process parameters and doping modification using atmospheric plasma spraying technology.Finally,the high temperature application performance of YZTO coating was studied.It provides new experimental basis and data support for the development of low emissivity materials.