Effect of diamond nanoparticles on the performance of PEO coatings on zirconium: Microstructural, mechanical, corrosion, and tribological properties

This study investigates the effect of diamond nanoparticle concentrations (0.2, 0.5, and 0.8 g/L) on the performance of PEO coatings on zirconium substrates, focusing on their microstructural, mechanical, corrosion, and tribological properties. The results indicate that diamond nanoparticles filled the coating pores, reducing surface roughness and increasing deposition rates and coating thickness as the concentration increased. Despite these modifications, the phase composition remained unchanged due to the high melting point of the nanoparticles. The coating with 0.5 g/L nanoparticle concentration exhibited the highest hardness (12.64 GPa) and Young's modulus (245 GPa), representing a 405 % increase in hardness compared to pure zirconium. Electrochemical tests showed that the 0.5 g/L sample had the best corrosion resistance , acting as an effective barrier against corrosive agents, with a 99.54 % reduction in corrosion current density compared to pure zirconium. Furthermore, tribological analysis demonstrated improved wear resistance and lower friction, with the 0.5 g/L coating achieving the lowest coefficient of friction of 0.224. Overall, the incorporation of diamond nanoparticles significantly enhanced the corrosion, mechanical, and tribological properties of the coatings, with 0.5 g/L emerging as the most effective concentration based on quantitative results. • Diamond nanoparticles (0.2, 0.5, and 0.8 g/L) were incorporated into PEO coatings on zirconium, enhancing their microstructural, mechanical, corrosion, and tribological properties. • Increasing nanoparticle concentration reduced surface roughness, improved deposition rates , and increased coating thickness, with optimal performance at 0.5 g/L. • No phase alterations were observed in the coatings, as the high melting point of the nanoparticles prevented structural changes. • The 0.5 g/L coating showed a 405% increase in hardness and significantly improved corrosion resistance compared to pure zirconium and other coatings. • Tribological tests demonstrated enhanced wear resistance and reduced friction, with 0.5 g/L of nanoparticles providing the best overall performance.