The Influence Factors Of Structure And Performance Of Supersonic Plasma Sprayed 8YSZ Thermal Barrier Coatings Research

In recent years,with the development of aerospace and civil aviation technology,working temperature of the hot section components of gas turbine is becoming higher.In the development of new super alloy materials and cooling technology,meanwhile,using the plasma spraying?APS?or electron beam physical vapor deposition?EB-PVD?has been used to produce thermal barrier coatings with resistance to high temperature oxidation and heat insulation function on the surface of the hot section components,which has been gradually becoming one of the most active subjects in the field of international high temperature coating at this century.In order to improve the working temperature and prolong the service life of thermal barrier coatings,countries around the world pour manpower and material resources into investigation of coating structure,bonding materials,ceramic materials,preparation process and coating failure mechanism of the thermal barrier coating.Due to the high flame temperature,small thermal impact on the work piece and high velocity of jet flow,the supersonic plasma spraying technique can be used to prepare the coatings of almost all kinds of materials.Especially for all kinds of refractory metals,alloy,the high melting point ceramic and cermet,supersonic plasma spraying has been found wide application.It is known that there are many effect factors on the quality of thermal barrier coatings produced by plasma spraying,in which powder character,nozzle type and spraying parameters are the most important factors to affect the performance stability and service life of resulted spraying coatings.However,reports on the effect of the above parameters on the temperature and velocity of supersonic plasma spraying particles,and the quality and performance of coatings are scarce in international and internal journals.In this work,the self-developing high efficiency supersonic plasma spraying system?HEPJet?was used and the effects of character of 8YSZ?8%Y₂O₃-ZrO₂?ceramic powders,nozzle type and spraying parameters on the temperature and velocity of spraying particles,and the quality and performance of coatings were studied,which provides a solid test and theoretical basis for the application and further promotion of high efficiency plasma spraying technology.The main contents and innovations of this work are as follows:?1?According to the characteristics of different nozzles,the optimized nozzle types applicable for various materials were determined.?2?By contrast experiments,the influence of the main properties of powder material on the supersonic plasma spraying process was investigated.?3?The systematically analysis of the micro-structure,porosity,component and hardness of coatings were completed by SEM,XRD and HVS-100,and the influences of spraying parameters on the coatings performance were obtained.