Synthesis of PPy–ZnO coatings on laser textured W substrates for ameliorating the adhesion strength of the interface

Abstract This paper aimed to improve the adhesion strength of the polypyrrole–zinc oxide/tungsten substrate (PPy–ZnO/W) system. Groove-like textures with different depths on the surface of tungsten substrates were prepared using a laser treatment, and then PPy–ZnO nanocomposites were fabricated on substrates with or without textures via electrochemical polymerization. The effects of textures on the morphology, microstructure, mechanical properties, and electrical conductivity were systematically analyzed. Pull-out tests were employed to assess the adhesion strength of different coated samples. The results indicated that the adhesion strength of the PPy-ZnO coating can be significantly improved by applying a texture process to the W substrates. The coating deposited on the textured substrate with a depth of 5.4 μm had the strongest adhesion strength, reaching 4.14 ± 0.25 MPa, which was 75% higher than that of the untextured sample at 2.36 ± 0.25 MPa. This enhancement effect is mainly contributed to by the laser textured surface, which created a larger and mechanical anchoring interface between the coating and substrate, compacted the microstructure of the coating and activated the surface of the substrates.