18.稀土Y2O3和Gd2O3共掺杂对La2(Zr0.7Ce0.3)2O7陶瓷相结构及热膨胀系数的影响

稀土Y₂O₃和Gd₂O₃共掺杂对La₂(Zr_0.7Ce_0.3)₂O₇陶瓷相结构及热膨胀系数的影响

乔 璟，辛 娜，谢 敏，宋希文

（内蒙古科技大学 材料与冶金学院，内蒙古 包头 014010）

关键词：热障涂层；La₂(Zr_0.7Ce_0.3)₂O₇；萤石结构；热膨胀

中图分类号：TQ174. 75文献标识码：A

摘 要：采用固相合成法制备了(La_1-2xY_xGd_x)₂(Zr_0.7Ce_0.3)₂O₇(x = 0, 0.30, 0.35, 0.40, 0.45, 0.50)体系陶瓷材料。分别利用XRD、扫描电子显微镜和高温热膨胀仪对陶瓷材料的相组成、微观形貌及热膨胀系数进行测试。结果表明，掺杂量x = 0时为立方烧绿石结构， x ≥ 0.30时为立方萤１石结构；晶粒发育良好，晶界清晰；Y₂O₃和Gd₂O₃的掺杂可以有效的提高La₂(Zr_0.7Ce_0.3)₂O₇的热膨胀系数。

Structure and thermal expansion behaviorof La₂(Zr_0.7Ce_0.3)₂O₇with A-site partially substituted with equimolar Y₂O₃ andGd₂O₃

QIAOJing, XIN Na, XIE Min, SONG Xi-wen

(Materials and Metallurgy School , Inner Mongolia University of Science and Technology, Baotou 014010, China)

Key words: TBCs; La₂(Zr_0.7Ce_0.3)₂O₇;fluorite structure; thermal expansion

Abstract: The (La_1-2xY_xGd_x)₂(Zr_0.7Ce_0.3)₂O₇(x=0, 0.30, 0.35, 0.40, 0.45, 0.50) ceramicswere synthesized by a solid state reaction method. The phase structure,microstructure and thermal expansion coefficient of the ceramics werecharacterized by X-ray diffraction, scanning electron microscopy and high-temperaturedilatometer, respectively. The XRD results of the ceramicssintered at 1600 ℃ for 5 hindicate that theLa₂(Zr_0.7Ce_0.3)₂O₇ ceramic is composed of the pure pyrochlorestructure and the (La_1-2xY_xGd_x)₂(Zr_0.7Ce_0.3)₂O₇(x ≥ 0.30) ceramics are composed of the pure fluorite structure.The SEM results of the ceramics sintered at1600 ℃ for 5 h indicate that the grains grew upuniformly, the grain boundarieswere clean. The substitution of Y₂O₃and Gd₂O₃ resulted in an increase in the thermal expansioncoefficients.