Assessing the wear properties of plasma electrolytic oxidation TiO2 coatings incorporated ZrO2 nanoparticles on Cp-Ti in simulated body fluid

Abstract

TiO₂ oxide coatings incorporated ZrO₂ nanoparticles were prepared on Cp-Ti using the plasma electrolytic oxidation (PEO) process in electrolyte solutions containing dispersed ZrO₂ nanoparticles. The coatings’ microstructure, roughness, and composition were characterized using scanning electron microscopy (SEM), roughness profilometry, and X-ray diffractometry (XRD) analyses, respectively. The coatings’ friction and wear characteristics were examined using a ball-on-disk sliding test in a simulated body fluid (SBF) electrolyte. The as-prepared oxide coatings had a rough and porous surface structure, primarily consisting of rutile and/or anatase TiO₂, tetragonal ZrO₂, and ZrTiO₄. ZrO₂ nanoparticles were incorporated into the TiO₂ coating layers and were found on the surface or in the pores. The wear and friction behavior of the oxide coatings were influenced by the quantity of ZrO₂ nanoparticles (1 g/L, 3 g/L, and 5 g/L) in the electrolyte solution. The wear resistance of coatings improved by decreasing the wear rate by about 8 % (from 2.31 × 10⁻⁶ mm³/Nm to 2.11 × 10⁻⁶ mm³/Nm) when the ZrO₂ nanoparticles concentration in the electrolyte solution rose from 1 g/L to 5 g/L, because of the formation of more of harder ZrO₂ and ZrTiO₄ phases in the coatings.