Experimental Study and Mechanism Analysis of the Influence of Micro-Dimple Geometry on the Adhesion Strength of Textured Coatings

Abstract

Textured coating technology is an effective method to improve the friction and wear performance of mold surfaces. The adhesion strength at the interface between the texture and the coating is crucial for its long-term serviceability. This paper studies the adhesion strength of micro-dimple’s topography textured coatings, aiming to reveal the influence mechanism of micro-dimples on the adhesion strength of textured coating interfaces. Different diameters or texture area ratios of micro-dimples were prepared on the sample surface using a picosecond laser, followed by PVD coating deposition. Scratching tests and indentation tests were then conducted on the textured coating surface. The adhesion strength and crack propagation behavior of the coating on the surface of different samples were studied under dynamic and static contact conditions. The results showed that under dynamic contact conditions, the critical load for coating failure of most textured samples was higher than that of non-textured samples. As the depth and diameter of the micro-dimple’s topography increased, the critical load first increased and then decreased, with the maximum critical load being 14.9% higher than that of the non-textured samples. Under static contact conditions, almost no coating spalling was observed around the indentation on the surface of the micro-dimple’s topography textured coating, while the spalling areas of non-textured samples were mainly at the edges and surrounding areas of the indentation. In contrast, the spalling regions of the textured samples were primarily concentrated at the edges of the texture. It can be seen that the dimpled texture hinders crack propagation and reduces the interlocking network of cracks, thereby reducing coating spalling. The research results provide important theoretical guidance for the design and optimization of textured coatings on mold surfaces.