Effects of texture spacing and bulges of bionic sinusoidal texture on the adhesion properties and fracture mechanism of plasma-sprayed coatings

• Published in: Surface & coatings technology 2020-07, Vol.393, p.125772, Article 125772
• Main Authors: Zhan, Xianghua, Yi, Peng, Liu, Yancong, Jiang, Yongliang, Jin, Yanchao, Dong, Guixin, Zhang, Yongang
• Format: Article
• Language: English
• Subjects: Adhesion strength; Adhesion tests; Adhesive strength; Bionic sinusoidal texture; Bionics; Bulge; Coatings; Failure analysis; Failure modes; Fracture mechanics; Laser beam texturing; Laser texturing; Morphology; Plasma spray; Sprayed coatings; Texture; Texture spacing
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2020.125772

Ni based MoS2 coatings were prepared on grit-blasted and bionic sinusoidal laser-textured surfaces by using an atmospheric plasma spray. The effects of bionic sinusoidal textures with different texture spacing and bulges on the adhesion strength of the coatings were investigated using the ASTM 633 adhesion test. The cross-sectional microstructure of the coatings and the fracture morphology were characterized to investigate the coating deposition and fracture mechanism. Results showed that the texture spacing and bulge significantly affect coating adhesion. Thus, the decrease in texture spacing and the existence of texture bulges significantly increased the adhesion strength. The comparison of textured surfaces with and without bulges showed that the exposed plain areas were harmful to the improvement of coating adhesion. An optimal texture spacing for coating adhesion improvement was observed for the textured surfaces with bulges. Fracture analysis showed that the mix failure mode mainly occurred without bulges, and adhesive failure occurred in almost all plain areas. With the existence of bulges, the adhesive failure only dominated when the texture spacing was very large or very small, otherwise, the fracture mechanism was dominated by cohesive failure. [Display omitted] •A bionic sinusoidal texture is designed.•Effects of texture spacing and bulges on the coating adhesion are studied.•The decrease in texture spacing can remarkably enhance coating adhesion.•The removal of the bulges is harmful for the enhancement of coating adhesion•The existence of exposed plain areas is harmful to coating adhesion.