Yb2O3‐Gd2O3 codoped strontium zirconate composite ceramics for potential thermal barrier coating applications

Abstract

AbstractStrontium zirconate (SrZrO3) has been considered as a promising thermal barrier coating (TBC) material for application in gas turbine engines; however, the phase transition problem limits its application. In this study, an Yb2O3 and Gd2O3 codoped SrZrO3 system with excellent properties was reported. Yb2O3‐Gd2O3 codoped SrZrO3 ceramic powders [Sr0.8(Zr0.9Yb0.05Gd0.05)O2.75, SZYG/YGZO], [Sr(Zr0.9Yb0.05Gd0.05)O2.95, SZYG] and pure SrZrO3 (SZO) powders were produced by a conventional solid‐state reaction method. The XRD and Raman results show that, the composite SZYG/YGZO ceramics consist of the SZO and Yb0.5Zr0.5O1.75 phases with a low thermal conductivity of ~1.3 W/(m·K) at 1000°C, which is at least 40% lower than that of the SZO ceramics. The TG‐DSC results show that the SZYG/YGZO ceramics have no phase transition in the temperature range of 600 to 1400°C. The thermal expansion coefficient of the SZYG/YGZO ceramics reaches 10.9 × 10−6 K−1 (1250°C). In addition, the fracture toughness of the SZYG/YGZO ceramics increases by more than 30% compared with the SZO ceramics, and this can be attributed to the presence of the Yb0.5Zr0.5O1.75 phase.