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2691 |
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Phase composition and ionic conductivity of plasma sprayed samarium zirconate coatings |
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Xinghua Zhong / Shanghai Institute of Ceramics, Chinese Academy of Sciences, P.R. China Jianhua Yu / Shanghai Institute of Ceramics, Chinese Academy of Sciences., China Huayu Zhao/ Shanghai Institute of Ceramics, Chinese Academy of Sciences., China Xiaming Zhou/ Shanghai Institute of Ceramics, Chinese Academy of Sciences., China Shunyan Tao*/ Shanghai Institute of Ceramics, Chinese Academy of Sciences., China Chuanxian Ding/ Shanghai Institute of Ceramics, Chinese Academy of Sciences., China |
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The rare earth zirconates (Ln2Zr2O7, Ln = LaGd) have high ionic conductivity and high temperature stability making them as attractive candidates for solid oxide fuel cells application. In this paper, Sm2Zr2O7 coatings were deposited by plasma spraying and the effect of thermal aging temperature on their phase composition, microstructure and ionic conductivity was explored. The X-ray diffraction results showed that the as-sprayed Sm2Zr2O7 coating exhibited a defective fluorite-type structure, while its degree of ordering was improved due to the thermal exposure at high temperatures. After thermal aging at 1673 K for 50 h, the coating with pyrochlore-type structure was observed. The scanning electron microscope examination revealed that the porosity and interlamellar microcrack density of coatings decreased with increasing thermal aging temperature. The ionic conductivity of coating samples measured by electrochemical impedance spectroscopy obeyed the Arrhenius relation. The ionic conductivity of the as-sprayed Sm2Zr2O7 coatings was lower than that of the heat treated one, which increased with the interlamellar microcrack healing, and the activation energy decreased as their structure became ordered. |