Effect of TiO2 and ZrO2 reinforcements on properties of Al2O3 coatings fabricated by thermal flame spraying
(1. Laboratory of Mechanics, Materials and Energetic, Faculty of Technology,
University of Bejaia, 06000 Bejaia, Algeria;
2. Laboratory of Mechanics, Faculty of Engineering Sciences, Campus Chaabet-Ersas,
University of Constantine, 25000 Constantine, Algeria;
3. Mechanical Laboratory of Structure and Energetic, Mechanical Engineering Department,
University of Tizi-Ouzou, 15000 Tizi-Ouzou, Algeria;
4. Laboratory Processes for Materials, Energy, Water and Environment, Faculty of Science and Technology,
University of Bouira, 10000 Bouira, Algeria)
University of Bejaia, 06000 Bejaia, Algeria;
2. Laboratory of Mechanics, Faculty of Engineering Sciences, Campus Chaabet-Ersas,
University of Constantine, 25000 Constantine, Algeria;
3. Mechanical Laboratory of Structure and Energetic, Mechanical Engineering Department,
University of Tizi-Ouzou, 15000 Tizi-Ouzou, Algeria;
4. Laboratory Processes for Materials, Energy, Water and Environment, Faculty of Science and Technology,
University of Bouira, 10000 Bouira, Algeria)
Abstract: The alumina composite coatings reinforced with 25% ZrO2 (denoted as AZ-25) and 3% TiO2 (denoted as AT-3) were deposited on low carbon steel using a thermal flame spraying. The microstructure, phase composition, microhardness and tribological properties of the coatings were investigated. The XRD results of the coatings reinforced by TiO2 (AT-3) revealed the presence of α-Al2O3 phase as matrix and new metastable phases of γ-Al2O3 and κ-Al2O3. However, the coatings reinforced by ZrO2 (AZ-25) consist of α-Al2O3 as matrix, q-ZrO2 and m-ZrO2. In most studied conditions, the AT-3 coating displays a better tribological performance, i.e., lower coefficient of frictions and wear rates, than the AZ-25 coating. It was also found that the microhardness of the coatings was decreased with the reinforcement of ZrO2 and increased with TiO2.
Key words: thermal spraying; coatings; reinforcements; friction coefficient; wear rate