复合钙钛矿型Ba(Zn_(1/3)Ta_(2/3))O_(3)陶瓷作为热障涂层陶瓷层材料的基础性能评价

Basic Performance Evaluation of Composite Perovskite Ba(Zn_(1/3)Ta_(2/3))O_(3)Ceramic as Ceramic Coating Material for Thermal Barrier Coatings

以BaCO_(3)、ZnO、Ta_(2)O_(5)为原料,采用固相反应法制备了Ba(Zn_(1/3)Ta_(2/3))O_(3)(BZT)陶瓷材料。对BZT的物相结构、高温相稳定性、热导率、热膨胀系数和喷涂工艺适应性进行表征研究,并与同类Ba(Mg_(1/3)Ta_(2/3))O_(3)(BMT)、Ba(Ni_(1/3)Ta_(2/3))O_(3)(BNT)和Ba(Sr_(1/3)Ta_(2/3))O_(3)(BST)对比,以评价BZT作为热障涂层陶瓷层材料的应用潜力。结果表明,BZT在室温至1500℃内无相变,且经1600℃长时处理48 h后不分解,表现出良好的高温相稳定性;在1200℃,BZT的热导率仅为1.65 W·m^(-1)·K^(-1),明显低于BMT(2.57 W·m^(-1)·K^(-1)),BNT(2.56 W·m^(-1)·K^(-1))和BST(2.11 W·m^(-1)·K^(-1)),呈现出更好的高温隔热能力;同时,BZT在200~1400℃内的平均热膨胀系数为11.3×10^(-6)K^(-1),高于BNT(10.7×10^(-6)K^(-1))和BST(8.1×10^(-6)K^(-1));由等离子喷涂制备的BZT涂层物相为单一的钙钛矿结构,所制备的YSZ/BZT双陶瓷层涂层层间结合良好。综合考虑,BZT陶瓷有望成为新型热障涂层的候选材料。

Ba(Zn_(1/3)Ta_(2/3))O_(3)(BZT) ceramic was synthesized by a solid-state reaction method using BaCO_(3), ZnO, and Ta_(2)O_(5)powders as the raw materials. The phase structure, high-temperature phase stability, thermal conductivity, coefficient of thermal expansion, and adaptability of spraying process of BZT were investigated and characterized, and compared with Ba(Mg_(1/3)Ta_(2/3))O_(3)(BMT), Ba(Ni_(1/3)Ta_(2/3))O_(3)(BNT), and Ba(Sr_(1/3)Ta_(2/3))O_(3)(BST) to evaluate the potential application of BZT as a top coating material for thermal barrier coatings. The results indicate that no phase transition occurs during the heating from room temperature to 1500 ℃, and BZT is quite stable up to 1600 ℃ for 48 h, without the occurrence of decomposition, showing excellent high-temperature phase stability. The thermal conductivity of BZT is only 1.65 W·m^(-1)·K^(-1)at 1200 ℃, which is significantly lower than those of BMT(2.57 W·m^(-1)·K^(-1)), BNT(2.56 W·m^(-1)·K^(-1)) and BST(2.11W·m^(-1)·K^(-1)), showing better high-temperature heat insulation ability. The average coefficient of thermal expansion of 11.3×10^(-6)K^(-1)for BZT from 200 ℃ to 1400 ℃ is higher than these of BNT(10.7×10^(-6)K^(-1)) and BST(8.1×10^(-6)K^(-1)). The plasma-sprayed BZT coating has single perovskite structure, and the adhesion between the layers is compact for YSZ/BZT double-ceramic-layer coatings. Therefore, BZT ceramic might be a promising candidate material for novel thermal barrier coatings.