Ba(Mg1/3Ta2/3)O3热障涂层的制备及抗热震性能研究

Preparation and thermal shock resistance of Ba(Mg1/3Ta2/3)O3 thermal barrier coatings

摘要:

本文以BaCO₃、MgO、Ta₂O₅为原料,采用固相反应法合成了Ba(Mg_1/3Ta_2/3)O₃(简称BMT)陶瓷粉末,利用大气等离子喷涂技术制备了BMT/YSZ双层陶瓷涂层。利用XRD、SEM和金相显微镜检测了BMT粉体及涂层的物相组成和显微结构。采用水淬法考核了涂层的抗热震性能。结果表明：1450℃下煅烧4h可合成出具有复合钙钛矿结构的BMT粉末,粉末具有良好的高温相结构稳定性。等离子喷涂制备的BMT/YSZ涂层组织致密,涂层系统中各界面结合紧密。涂层在室温至1150℃间热震9次后发生片状剥落,剥落位置位于BMT层间,BMT材料低的断裂韧性和第二相Ba₃Ta₅O₁₅的存在是导致涂层失效的主要原因。

Abstract:

Ceramic powder Ba(Mg_1/3Ta_2/3)O₃ (BMT) was synthesized by the way of solid-phase synthesis method with the raw materials powder of BaCO₃、MgO、Ta₂O₅. BMT/YSZ coatings were prepared by atmospheric plasma spraying (APS). The phase composition and microstructure of the BMT powder and coatings were analyzed by XRD, SEM and optical microscope. The thermal shock resistance was evaluated by water quenching. The results show that the BMT powder with perovskite structure can be synthesized at 1450 ℃ for 4 h. The BMT powder reveals desirable phase stability. The BMT/YSZ coatings have a compact microstructure and higher binding strength between every coating. Spallation was observed within the BMT coatings after 9 cycle thermal shock testing from 1150 ℃to room temperature. Low fracture toughness of BMT and the precipitation of Ba₃Ta₅O₁₅ phase are the main reason for failure of BMT/YSZ coatings.