Effect of multiple dissimilar nanoparticles in Ni–W alloy matrix composite coating and evaluation of surface-mechanical, corrosion, and hydrophobic properties

Abstract

TiO2 and ZrO2 nanoparticles reinforced Ni–W-based composite coatings were prepared on mild steel substrate via pulse electrodeposition technique under constant operating parameters. During the deposition process, TiO2 content was maintained constant throughout the process whereas, ZrO2 content has been varied. Phase evolution, microstructure, and compositional changes of coatings were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive microscopy, respectively. Microhardness and wear tests were conducted on composite coatings to evaluate the surface mechanical properties. The corrosion behaviour of the composite coatings was studied by potentiodynamic polarization and electrochemical impedance spectroscopy in a 3.5% NaCl solution. The topography of certain composite coatings has been examined by an atomic force microscope (AFM). Besides, a wettability test was conducted to study the hydrophobic properties of composite coatings. Experimental results demonstrated that ZrO2 nanoparticle's addition under fixed TiO2 content in deposition bath play a crucial role to improve the surface-mechanical, corrosion, and hydrophobic properties of the coating. The maximum hardness (1074 HV0.05), wear and corrosion properties were observed in Ni–W-5g/L TiO2-15g/L ZrO2 composite coating.