(Yb_(0.25)Lu_(0.25)Er_(0.25)Y_(0.25))_(2)Si_(2)O_(7)高熵硅酸盐热环境障涂层的性能研究

Properties of(Yb_(0.25)Lu_(0.25)Er_(0.25)Y_(0.25))_(2)Si_(2)O_(7) High Entropy Silicate Thermal Environmental Barrier Coating

通过高熵化设计制备了一种新型焦硅酸盐涂层材料(Yb_(0.25)Lu_(0.25)Er_(0.25)Y_(0.25))_(2)Si_(2)O_(7),采用大气等离子喷涂(APS)在碳化硅纤维增强碳化硅陶瓷复合材料(SiC_(f)/SiC-CMCs)表面制备了(4RE_(0.25))_(2)Si_(2)O_(7)一体化热环境障涂层(TEBCs)体系和LaMgAl_(11)O_(19)/Lu_(2)Si_(2)O_(7)热/环境障涂层(T/EBCs)体系。通过研究两种涂层体系的微观结构、热物理性能、水氧腐蚀性能以及热循环寿命等结果发现:APS制备的(4RE_(0.25))_(2)Si_(2)O_(7)涂层从室温到1500℃为稳定的β相,(4RE_(0.25))_(2)Si_(2)O_(7)涂层不存在成分偏析,热导率和热膨胀系数相对Lu_(2)Si_(2)O_(7)涂层有所降低,更适合作为一体化TEBCs使用;(4RE_(0.25))_(2)Si_(2)O_(7)TEBCs体系的水氧腐蚀寿命高于80 h,LaMgAl_(11)O_(19)/Lu_(2)Si_(2)O_(7)T/EBCs体系的水氧腐蚀寿命低于80 h;(4RE_(0.25))_(2)Si_(2)O_(7)TEBCs体系的热循环寿命为168次;高熵化设计使焦硅酸盐涂层CTE适配度提高,断裂韧性增强,进而增加了TEBCs体系的热循环寿命。

A new pyrosilicate coating material(Yb_(0.25)Lu_(0.25)Er_(0.25)Y_(0.25))_(2)Si_(2)O_(7) was prepared by high entropy design.(4RE_(0.25))_(2)Si_(2)O_(7) integrated thermal environmental barrier coatings(TEBCs)and La Mg Al_(11)O_(19)/Lu_(2)Si_(2)O_(7) thermal/en‐vironmental barrier coatings(T/EBCs)were prepared by atmospheric plasma spraying(APS)on the surface of silicon carbide fiber reinforced silicon carbide ceramic composites(Si C_(f)/Si C-CMCs)system.By studying the mi‐crostructure,thermophysical properties,water-oxygen corrosion properties and thermal cycle life of the two coat‐ing systems,it is found that the(4RE_(0.25))_(2)Si_(2)O_(7) coating prepared by APS is a stable β phase from room temperature to 1500℃,the(4RE_(0.25))_(2)Si_(2)O_(7) coating does not have component segregation,the thermal conductivity and thermal expansion coefficient are lower than those of Lu_(2)Si_(2)O_(7) coating,and it is more suitable for use as integrat‐ed TEBCs.The water-oxygen corrosion life of(4RE_(0.25))_(2)Si_(2)O_(7) TEBCs system is higher than 80 h,and that of La Mg Al_(11)O_(19)/Lu_(2)Si_(2)O_(7) T/EBCs system is lower than 80 h.The thermal cycle life of(4RE_(0.25))_(2)Si_(2)O_(7) TEBCs system is 168 times.The high entropy design can improve the CTE fit and fracture toughness of the coke silicate coat‐ing,and thus increase the thermal cycle life of TEBCs system.