Effects of isothermal heat treatment on tribological and electrochemical performances of alumina-based coatings with monoclinic zirconia

Purpose 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. Design/methodology/approach Al 2 O 3 and Al 2 O 3 -ZrO 2 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. Findings X-ray diffraction measurements revealed an increase in the a-Al 2 O 3 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. Originality/value 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.% ZrO 2 . These improvements were more pronounced for the Al 2 O 3 -ZrO 2 coating than the pure alumina Al 2 O 3 coating. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0190/