Preparation and properties analysis of Ni-W/Si3N4 composite coating on 7075 aluminum alloy

Abstract

To enhance the performance of 7075 aluminum alloy in aerospace and marine applications, Ni-W/Si₃N₄ composite coatings are developed via vertical electrodeposition. The effects of Si₃N₄ concentrations on the microstructure, mechanical properties, and corrosion resistance of coatings are investigated. The optimal concentration of 10 g/L Si₃N₄ significantly enhanced performance, increasing microhardness by 55 %, reducing the friction coefficient and wear rate by 46.9 % and 31.9 %, respectively, and improving corrosion resistance by 98.9 %. Microstructural analysis revealed that Si₃N₄ altered the phase structure of the Ni-W alloy and refined the grain size. The incorporation of Si₃N₄ reduced surface roughness by 38.9 % and filled voids, thereby enhancing the shielding effect of the coating. XPS results indicated Si₃N₄ influenced the content of metallic W in coatings, with superior coating performance observed when the metallic W content was at its highest. These findings highlight the potential of Ni-W/Si₃N₄ coatings for enhancing durability and performance.