Research on Cleaning Mechanism of Anti-Erosion Coating Based on Thermal and Force Effects of Laser Shock

Abstract

TiN coating plays a positive role in improving the abrasion resistance and impact resistance of aero-engines in sand and dust environments. However, little research has been done on the laser cleaning of TiN coatings that failed on aircraft engines. In this paper, TiN coatings are deposited on Ti6Al4V alloys by magnetic filtered cathodic vacuum arc (MFCVA). The TiN coating was laser cleaned with different parameters. By analyzing coating morphology, surface composition and sample profile, the research reveals the morphological change of the TiN coating after cleaning and the laser cleaning mechanism. The results show that for TiN–Ti6Al4V structure, when the laser average power density is 2.54 × 103 W/cm2, the cleaning mechanism of the coating is thermal expansion; The laser average power density is increased to 5.08 × 103 W/cm2, the cleaning mechanism is thermal expansion, accompanied by the thermal melting of the substrate, a small amount of molten substrate overflows from the crack. When the laser average power density is 5.08 × 103 W/cm2 and the number of cleanings doubles, the cleaning direction is perpendicular to each other, the cleaning mechanism is thermal expansion and thermal melting, both the substrate and the coating are melted, and the cleaning is obviously effective.