Enhanced Microstructural, Mechanical, and Corrosion Properties of Cu–Co Coatings Reinforced with Al₂O₃ Nanoparticles

In this study, X/Al₂O₃ composite coatings were fabricated on stainless steel substrates via electrodeposition, and the effects of Al₂O₃ nanoparticles on the microstructure, mechanical properties, surface morphology, and corrosion behavior were investigated. Cross-sectional optical microscopy revealed that the incorporation of Al₂O₃ nanoparticles increased the coating thickness by approximately ۱۹%, attributed to modified deposition kinetics and enhanced cathodic current efficiency. EDS analysis confirmed the successful formation of the composite coating and the uniform distribution of Al₂O₃ nanoparticles within the metallic matrix. Surface roughness measurements showed a ۱۰۹% increase in roughness due to disrupted grain growth and the formation of additional nucleation sites. Vickers hardness testing indicated a significant improvement of ۶۳.۵% compared to the base metallic coating, resulting from strengthening mechanisms such as dispersion hardening, grain refinement, and hindrance of dislocation motion. Potentiodynamic polarization tests demonstrated that the X/Al₂O₃ composite coating exhibited enhanced corrosion resistance, associated with reduced porosity, increased coating density, and the inhibitory effect of Al₂O₃ nanoparticles on the penetration of corrosive species. Overall, the results indicate that the incorporation of Al₂O₃ nanoparticles into the X coating improves both the mechanical properties and corrosion resistance, making this composite coating a promising candidate for engineering applications in corrosive environments.

Keywords:

Cu–Co composite coating , Al₂O₃ nanoparticles , corrosion resistance , surface roughness , Microhardness