(Y_(0.2)Gd_(0.2)Dy_(0.2)La_(0.2)Sm_(0.2))TaO_(4)高熵陶瓷材料的结构、性能及抗侵蚀行为研究

Structure,properties and corrosion resistance of high entropy(Y_(0.2)Gd_(0.2)Dy_(0.2)La_(0.2)Sm_(0.2))TaO_(4)ceramic materials

为满足新一代航空发动机对新型热障涂层材料的迫切需求,以高纯氧化物(Y_(2)O_(3)、Gd_(2)O_(3)、Dy_(2)O_(3)、Sm_(2)O_(3)、La_(2)O_(3)、Ta_(2)O_(5))为原料,按化学计量比配料,经1200~1750℃保温5 h固相反应,制备了高熵稀土钽酸盐(Y_(0.2)Gd_(0.2)Dy_(0.2)La_(0.2)Sm_(0.2))TaO_(4)材料,简称为(5RE_(0.2))TaO_(4)材料。研究了材料的物相组成、显微结构、热学性能、力学性能和抗CaO-MgO-Al_(2)O_(3)-SiO_(2)(CMAS)侵蚀行为。结果表明:1)(5RE_(0.2))TaO_(4)陶瓷材料为单斜结构,存在明显铁弹畴;2)该材料经1750℃烧后具有极低的热导率(1.65 W·m^(-1)·K^(-1),600℃)和较高的热膨胀系数(10.2×10^(-6)K^(-1),1200℃);3)由于独特的铁弹增韧效应,经1750℃烧后(5RE_(0.2))TaO4材料的断裂韧性达到2.4 MPa·m^(1/2);4)(5RE_(0.2))TaO_(4)与CMAS熔体作用后形成反应层,表现出了优异的抗侵蚀性能。

In order to meet the urgent demand of new thermal barrier coating materials for a new generation of aero-engines,a high entropy rare earth tantalate(Y_(0.2)Gd_(0.2)Dy_(0.2)La_(0.2)Sm_(0.2))TaO_(4)material,abbreviated as(5RE 0.2)TaO 4,was developed using high-purity oxides(Y_(2)O_(3),Gd_(2)O_(3),Dy_(2)O_(3),Sm_(2)O_(3),La_(2)O_(3),Ta_(2)O_(5))as raw materials according to the stoichiometric ratio,and insulating at 1200-1750℃for 5 h for a solid phase reaction.The phase composition,microstructure,thermal properties,mechanical properties,and CMAS(CaO-MgO-Al_(2)O_(3)-SiO_(2))corrosion resistance of the material were studied.The results show that:(1)the(5RE 0.2)TaO_(4)ceramic material has a monoclinic structure with obvious ferroelastic domain;(2)the material fired at 1750℃exhibits extremely low thermal conductivity(1.65 W·m^(-1)·K^(-1),600℃)and high thermal expansion coefficient(10.2×10^(-6)K^(-1),1200℃);(3)due to the unique ferroelastic toughening effect,the fracture toughness of the(5RE_(0.2))TaO_(4)material fired at 1750℃reaches 2.4 MPa·m^(1/2);(4)(5RE_(0.2))TaO_(4)reacts with CMAS melt forming a reaction layer,showing excellent corrosion resistance.