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

In this study, the Yb–Y co-doped SrZrO 3 (SZ) coatings [SZYY-1 (Sr 1.0 (Zr 0.9 Yb 0.05 Y 0.05 )O 2.95 ), SZYY-2 (Sr 0.9 (Zr 0.9 Yb 0.05 Y 0.05 )O 2.85 ), and SZYY-3 (Sr 0.8 (Zr 0.9 Yb 0.05 Y 0.05 )O 2.75 )] 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 .