Microstructure and properties of Al 2 O 3 -ZrO 2 -Y 2 O 3 coatings during high temperature and thermal shock resistance
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Microstructure and properties of Al2O3‑ZrO2‑Y2O3 coatings during high temperature and thermal shock resistance Wen‑Wei Sun1 · Xiao‑Long Wang1 · Xiao‑Wen Sun1 · Yong Yang1 · Chen Zhang1 · Yan‑Wei Wang1 · Yu‑Hang Cui1 · Yu‑Duo Ma1 Received: 3 June 2020 / Accepted: 17 July 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Al2O3-ZrO2 composite coatings were fabricated by plasma spraying Al2O3-ZrO2 composite powders with and without Y2O3 addition to learn the influence of Y 2O3 on high temperature stability of the coating. The two coatings both underwent phase transformation in the process of heat treatment. Specifically, XRD results showed that in the Al2O3-ZrO2-Y2O3 coating, Y3Al5O12 (YAG) phase existed after heating at 800 °C, and γ-Al2O3 all transformed to α-Al2O3 after heating at 1200 °C, so the composition of the coating was t-ZrO2, α-Al2O3 and YAG after heating at 1200 °C, while in the A l2O3-ZrO2 coating, the final coating consisted of t-ZrO2 and α-Al2O3 beacuse γ-Al2O3 all transformed to α-Al2O3 after heating at 1200 °C. The amorphous phase in the two as-sprayed coatings had been crystallized completely after heat treatment at 1200 °C. Heat treatment can reduce the porosity and improve the hardness of the two coatings, and YAG phase can also improve the hardness. The coating with TC4 substrate had better thermal shock resistance than it with Q235 steel substrate. The thermal shock resistance of the A l2O3-ZrO2-Y2O3 coating was better than that of the A l2O3-ZrO2 coating at same condition. NiCrAlY bonding layer can improve thermal shock resistance of the coating. Keywords Heat treatment · Al2O3 · ZrO2 · Thermal shock resistance · Y2O3
1 Introduction Al2O3 ceramics have high hardness and good wear resistance [1, 2]. Al2O3 coatings can be used on metal substrates to improve the wear resistance, mechanical properties, corrosion resistance and even the oxidation resistance of the metal substrate at high temperature [3, 4]. Nevertheless, plasmasprayed Al2O3 coatings have some defects, such as high porosity, poor toughness and low fracture toughness (KIC) value [5, 6]. Moreover, when the A l2O3 coatings were used in a high-temperature environment, it would fall off easily due to its poor performance in thermal shock resistance [7]. * Yong Yang [email protected]; [email protected] 1
Key Lab. for New Type of Functional Materials in Hebei Province, School of Materials Science and Engineering, State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology, Hebei University of Technology, Xiping Road No.5340, Beichen District, Tianjin 300401, People’s Republic of China
ZrO2 coatings have good thermal insulation and thermal shock resistance and could be applied on metal substrates for high-temperatures application [8–12]. However, Z rO2 coating is not suitable for application in wear due to its low hardness. Therefore, it is meaningful to combine the character
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