Journal of Inorganic Materials ›› 2019, Vol. 34 ›› Issue (4): 394-400.doi: 10.15541/jim20180276

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Thermophysical Property of Single-phase Strontium Zirconate Co-doped with Double Rare-earth Oxides as a Thermal Barrier Coating Material

Bo-Le MA1,2,Wen MA1,2(),Wei HUANG1,2,Yu BAI1,2,Rui-Ling JIA1,2,Hong-Ying DONG2,3   

  1. 1. School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051, China
    2. Inner Mongolia Key Laboratory of Thin Film and Coatings Technology, Hohhot 010051, China
    3. School of Chemical Engineering, Inner Mongolia University of Technology, Hohhot 010051, China
  • Received:2018-06-22 Revised:2018-08-29 Online:2019-04-20 Published:2019-04-15
  • Contact: Wen MA E-mail:w.ma@imut.edu.cn
  • Supported by:
    National Natural Science Foundation of China(51462026);National Natural Science Foundation of China(51672136);Natural Science Foundation of Inner Mongolia(2017MS0503)

Abstract:

Due to the different vapor pressures between SrO and ZrO2, composition of air plasma sprayed (APS) SrZrO3 coating deviates from stoichiometric SrZrO3, resulting in formation of second phase ZrO2 in the as-sprayed SrZrO3 coating. To obtain single-phase coating with high phase stability, the Sr1.1(Zr0.9Yb0.05Gd0.05)O3.05 powder with excess Sr was synthesized by solid state reaction and spray drying, followed by air plasma spray to obtain the Sr1.1(Zr0.9Yb0.05Gd0.05)O3.05 coating. Thermo-physical properties and thermal cycling behavior of the Sr1.1(Zr0.9Yb0.05Gd0.05)O3.05 coating were investigated. Experimental results showed that the Sr1.1(Zr0.9Yb0.05Gd0.05)O3.05 coating had no second phase and showed a good high-temperature phase stability after heat- treatment at 1600 ℃ for 360 h. The sintering rate of the as-sprayed Sr1.1(Zr0.9Yb0.05Gd0.05)O3.05 coating was 7.27×10 -6 s -1. Thermal expansion coefficients (TECs) and thermal conductivity of the coating after heat-treatment at 1600 ℃ for 360 h were (9.0-11.0)×10 -6 K -1 (200-1400 ℃) and 2.83 W/(m?K) (1000 ℃), respectively. Thermal cycling lifetime of the Sr1.1(Zr0.9Yb0.05Gd0.05)O3.05/YSZ double ceramic layer coating was 1000 cycles, due to failure occurring in the Sr1.1(Zr0.9Yb0.05Gd0.05)O3.05 coating. Moreover, singe-phase Sr1.1(Zr0.9Yb0.05Gd0.05)O3.05 coating with SrZrO3 structure could be prepared by adding excess SrO in the feedstock, which showed higher TEC by co-dopping with Yb2O3 and Gd2O3 and sintering resistance than did the SrZrO3 coating. However, the thermal conductivity of the Sr1.1(Zr0.9Yb0.05Gd0.05)O3.05 coating is higher than that of the SrZrO3 coating because of the absence of the second phase.

Key words: thermal barrier coating, SrZrO3, thermal expansion, thermal conductivity

CLC Number: 

  • TQ174