Preparation of micro-textures on cemented carbide substrate surface by plasma-assisted laser machining to enhance the PVD tool coatings adhesion

Abstract

The micro-texture fabricated on the substrate surface of coatings is an established method for enhancing the Physical Vapor Deposition (PVD) coatings adhesion. Currently, laser micromachining is widely used to prepare the micro-texture. Nevertheless, it suffers from the problem of low fabrication quality, such as irregular texture edges and irregular protrusions inside the textures. Meanwhile, to achieve sufficient coating adhesion, the improvement of physical-chemical bonding between coatings and substrate is crucial. Here, we propose a plasma-assisted laser machining approach to fabricate micro-texture, and the effect of plasma/laser textures on the interfacial properties of PVD tool coatings, especially the physical-chemical bonding interfaces is revealed for the first time. The micro-topography, chemical structure and wettability of the plasma/laser textured substrate surface were investigated. The scratch tests on the coatings with different pretreated substrates and dry cutting experiments of stainless steel were carried out. Results show that the plasma/ laser textured substrate was conducive to coatings in terms of wettability, phase composition, roughness and hardness, and specific surface area, which could enhance the interfacial properties of PVD coatings. Thus, the critical load of plasma/laser textured coatings (FN, C2 = 103 N) exhibited higher values compared to that of the untextured one (FN, C2 = 70 N), and an obviously reduction in cutting force of FX up to 34.82 %, FY up to 36.15 %, FZ up to 27.71 % by plasma/laser textured coated tool was achieved. Furthermore, the mechanisms for the effects of plasma/laser textures on the coating adhesion were discussed.