Changes in high-temperature thermal properties of modified YSZ with various rare earth doping elements. Issue 6 (15th March 2022)

• Record Type: Journal Article
• Authors: Jeon, Hakbeom; Lee, Inhwan; Oh, Yoonsuk
• Is Part Of: Ceramics international. Volume 48:Issue 6(2022)
• Page Start: 8177
• Page End: 8185
• Publication Date: 2022-03-15
• Subjects: Thermal barrier coatings -- Modified YSZ -- Thermal conductivity -- High-temperature thermal property; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2021.12.020
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: To protect the high-temperature components of gas turbines, 6–8 wt.% yttria stabilised zirconia (YSZ) has been extensively used as a thermal barrier coating (TBC) material. However, its application is severely limited at high temperatures because of zirconia phase transition and sintering densification above 1200 °C. This study developed modified YSZ with enhanced high-temperature thermal properties owing to the addition of various rare-earth doping elements. Among the various rare earth-doped compositions, all the thermal properties were significantly improved in compositions containing scandium, gadolinium, and dysprosium. Furthermore, in the selected compositions, the high-temperature thermal properties were analysed under heat treatment conditions of 1300 °C, with a target turbine inlet temperature (TIT) of 1500 °C. The high-temperature phase stability of the tetragonal phase was significantly improved in the newly developed compositions, and they exhibited glass-like low thermal conductivity (∼0.984 W/mK) due to the influence of lattice distortion caused by the differences in the substituent-ion mass and size, and the oxygen vacancies. Moreover, there was notable improvement in the thermal expansion coefficient (∼11 × 10 −6 /K) and resistance to high-temperature densification.