The purpose of this study is to explore the possibility of enhancing the tribological and electrochemical performances of alumina coating using monoclinic zirconia addition and post-heat treatment.
Al2O3 and Al2O3-ZrO2 coatings were deposited on plain steel by flame-wire spraying. The influence of zirconia addition and post-treatment (900? for two hours) on phase composition and mechanical, tribological and electrochemical behaviors was investigated. Sliding dry tests were performed using a ball-on-disc test rig with WC-Co as the counter body. Polarization and impedance electrochemical responses were conducted under a 3.5 Wt.% NaCl solution.
X-ray diffraction measurements revealed an increase in the a-Al2O3 phase after heat treatment. Sliding dry tests showed that the abrasive wear mechanism was predominant for all coatings, leading to a good correlation between hardness and wear rates. However, the friction behavior had an opposite trend: the higher the hardness, the higher the coefficient of friction. The addition of zirconia significantly affected the corrosion resistance, which was more positive than the heat treatment effect.
Post-treatment showed beneficial effects on the wear and corrosion performance of alumina-based coatings, with a particularly noticeable improvement for the coating containing 30 Wt.% ZrO2. These improvements were more pronounced for the Al2O3-ZrO2 coating than the pure alumina Al2O3 coating.
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0190/
