大气等离子体喷涂Sm2Zr2O7涂层的结构和性能

摘要

稀土锆酸盐材料具有比Y2O3部分稳定ZrO2陶瓷低的热导率,是新型热障涂层的潜在候选材料之一.利用大气等离子体喷涂技术以喷雾造粒的Sm2Zr2O7粉体制备涂层,并在相同条件下沉积8wt%Y2O3稳定ZrO2涂层.对比评价了两种涂层的结构、热物理性能和力学性能.X射线衍射结果表明,制备态Sm2Zr2O7涂层为缺陷萤石结构.扫描电镜分析显示,Sm2Zr2O7和8wt%Y2O3稳定ZrO2涂层为典型的层状结构,内部有很多气孔、裂纹等缺陷.800℃测得的Sm2Zr2O7涂层的热导率为0.44 W/(m·K),比相同条件下测得的8wt%Y2O3稳定ZrO2涂层的热导率低～40%,两者的热膨胀系数相似.力学测试结果显示,Sm2Zr2O7涂层的抗折强度、硬度和弹性模量均低于8wt%Y2O3稳定ZrO2涂层.%Rare-earth zirconates with a pyrochlore structure have attracted great attention for potential application in thermal barrier coating systems. In the present work, Sm2Zr2O7 coatings were deposited by atmospheric plasma spraying technology. Their microstructure, thermo-physical and mechanical properties were examined, and compared with that of 8wt% Y2O3 stabilized ZrO2 coatings which was deposited under the same plasma spraying conditions. X-ray diffraction result shows that the as-sprayed Sm2Zr2O7 coating exhibits a defective fluorite structure. The thermal conductivity of Sm2Zr2O7 coating measured at 800°C is 0.44W/(Mk), about 40% lower than that of 8wt% Y2O3 stabilized ZrO2 coating, but the expansion coefficients of both coatings are similar. The Sm2Zr2O7 coating exhibits lower bending strength, microhardness and elastic modulus compared with 8wt% Y2O3 stabilized ZrO2 coating.