Effect of Laser-Textured Edge Splashing on Adhesion and Fracture Mechanism of Plasma-Sprayed Coatings.

The material surface was sinusoidally textured using nanosecond laser processing technology, and Ni-based MoS2 coatings were applied to the resultant surfaces via plasma spray. The adhesion of the coating was investigated through separate adhesion tests to assess the impact of retaining the fusion-sputtered splash bulges and subsequently grinding them off. The coating's cross-sectional microstructure and fracture morphology were characterized to investigate its deposition and fracture mechanisms. The comparison of textured surfaces with and without bulges has shown that the exposed plain areas diminish the coating's adhesion. Furthermore, the splash bulge also significantly affects the adhesion. Fracture analysis has demonstrated that the mixed failure mode is dominated by no uplift, and adhesive failure occurs in practically all plain areas. By analyzing specimen cross-sectional morphologies and extracting coating morphological features in and around the splash bulge, several aspects, such as filling and spreading mode, the state of sprayed droplets, porosity comparison, and crack formation mechanism and distribution, were investigated. Finally, it was concluded that the excessive or large splash bulges detrimentally impact the bonding properties of the coating. [ABSTRACT FROM AUTHOR]