**6.1 The internal influence law between composition, structure and performance of SPE coating**

The composition selection and structure design of the coating are the key to determine its erosion resistance. At present, the research on erosion resistant coatings has been carried out to optimize the performance from the aspects of preparation parameters, coating microstructure, etc. The research results are one-sided and lack of systematicness and guidance. There is little research on the internal correlation between the composition structure and the residual internal stress, the interlayer interface and the erosion resistance of the coating. At the same time, there is a lack of in-depth study on the mechanism of coating erosion failure. In addition, according to the service condition requirements of the erosion resistant coating, it should also have high temperature resistance, fatigue resistance and other related properties. Therefore, based on the above performance requirements and actual service conditions, a complete anti-erosion coating design theory, such as material selection and structure design, should be established.
