**6. Problems and consideration of SPE coating**

To sum up, in the research field of erosion resistant coatings, arc ion plating technology is widely used in the preparation of erosion resistant coatings for engine compressor blades. The coating system has gradually developed from binary TiN series coatings to multiple multilayer composite structure systems, and the comprehensive performance of the coatings has also been improved to varying degrees. However, up to now, the following problems still exist in the anti-erosion coating.
