高熵(Y_(0.2)Gd_(0.2)Dy_(0.2)Ce_(0.2)La_(0.2))TaO_(4)陶瓷材料的热学、力学及抗熔融硅酸盐环境沉积物侵蚀性能

Thermal,Mechanical and Molten Silicate Environmental Deposits Corrosion Resistance Properties of High-Entropy (Y_(0.2)Gd_(0.2)Dy_(0.2)Ce_(0.2)La_(0.2))TaO_(4) Ceramic Materials

新型高温热障涂层材料已成为新一代航空发动机发展的关键材料。本工作通过固相反应法合成了一种单斜结构的高熵稀土钽酸盐材料(Y_(0.2)Gd_(0.2)Dy_(0.2)Ce_(0.2)La_(0.2))TaO_(4)[(5RE_(0.2))TaO_(4)],研究了其热、力学性能及抗熔融硅酸盐环境沉积物(CMAS)侵蚀性能。结果表明:(5RE_(0.2))TaO_(4)具有极低的热导率(1.22 W·m^(–1)·K^(–1),600℃)和较高的热膨胀系数(10.3×10^(–6)K^(–1),1 200℃),与YSZ材料相比(2.1~2.7 W·m^(–1)·K^(–1),100~900℃)热导率下降了近42%。由于独特的铁弹增韧效应,其断裂韧性达2.8 MPa·m^(1/2),优于多数新型热障涂层材料。1 350℃不同时间及CMAS侵蚀后,(5RE_(0.2))TaO_(4)反应层厚度和渗透深度均显著小于YSZ材料,是一种极具应用潜力的新型热障涂层材料。

Novel high-temperature thermal barrier materials become the key materials for the development of new generation aeroengines.In this paper,a monoclinic high-entropy rare-earth tantalate material(Y_(0.2)Gd_(0.2)Dy_(0.2)Ce_(0.2)La_(0.2))TaO_4[(5RE_(0.2))TaO_4] was synthesized via solid-state reaction.The thermal,the mechanical and the molten silicate environmental deposits(CMAS) corrosion resistance were investigated.The results indicate that(5RE_(0.2))TaO_(4) exhibits a low thermal conductivity(i.e.,1.22 W·m~(–1)·K~(–1),600 ℃)and a high thermal expansion coefficient(i.e.,10.3×10~(–6)K~(–1),1 200 ℃),Compared with YSZ material(i.e.,2.1–2.7 W·m~(–1)·K~(–1),100–900 ℃),the thermal conductivity is decreased by 42%.The fracture toughness reaches 2.8 MPa·m~(1/2),which is superior to most thermal barrier coating materials because of its unique ferroelastic toughening effect.The thickness and penetration depth of the(5RE_(0.2))TaO_(4) reaction layer are smaller than those of the YSZ material after being corroded by CMAS at 1 350 ℃ for different durations.This material is a developed thermal barrier coating material with a great application potential.