Phase composition and thermophysical properties of Yb–Y Co-doped SrZrO3 coating prepared by suspension plasma spray

Abstract

In this study, the Yb–Y co-doped SrZrO3 (SZ) coatings [SZYY-1 (Sr1.0(Zr0.9Yb0.05Y0.05)O2.95), SZYY-2 (Sr0.9(Zr0.9Yb0.05Y0.05)O2.85), and SZYY-3 (Sr0.8(Zr0.9Yb0.05Y0.05)O2.75)] were deposited by SPS (Suspension plasma spray) using the corresponding co-precipitation prepared precursors suspension. In the three as-sprayed SZYY coatings, there were some typical suspension plasma-sprayed coating structures, such as columnar crystals, vertical cracks, and micro/nanopores.The TCs (Thermal conductivities) of the three as-sprayed SZYY coatings were 1.23–1.88, 0.80–1.41, and 0.88–1.43 W/(m · K) at 100–1400 °C, respectively, which were at least 19% lower than that of the SZ coating (1.25 W/(m · K), 1000 °C). The TECs (Thermal expansion coefficients) of the three as-sprayed SZYY coatings were (7.8–8.7) × 10−6, (8.0–9.8) × 10−6, and (8.1–9.8) × 10−6/K, respectively (200–1360 °C). The sintering coefficients of the three as-sprayed SZYY coatings were 5.69 × 10−6, 4.29 × 10−6, and 3.84 × 10−6/s, respectively. The SZYY-3 coating showed the best SR (Sintering resistance), followed by the SZYY-2 coating and SZYY-1 coating. The SPS SZYY-2 coating with good phase stability, low TC (Thermal conductivity) and good SR is a promising new TBCs (Thermal barrier coatings) material. It is expected to be an alternative TBCs material for the next generation of high performance gas turbines.