In-situ synthesis of gadolinium niobate quasi-binary composites with balanced mechanical and thermal properties for thermal barrier coatings  

作　　者：Yi HAN Peng-an ZONG Muzhang HUANG Zesheng YANG Yingjie FENG Wei PAN Peng ZHANG Chunlei WAN 

机构地区：[1]State Key Laboratory of New Ceramics and Fine Processing,School of Materials Science and Engineering,Tsinghua University,Beijing 100084,China [2]Institute of Welding and Surface Engineering Technology,Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China

出　　处：《Journal of Advanced Ceramics》2022年第9期1445-1456,共12页先进陶瓷（英文）

基　　金：This work was supported by the National Key R&D Program of China(No.2021YFB3702300);the National Natural Science Foundation of China(No.52022042);the China Postdoctoral Science Foundation(No.2019M650670).

摘　　要：Yttria-stabilized zirconia(YSZ)has been used as a thermal barrier coating(TBC)material in gas turbines for several decades.Although continuous efforts have been made to develop novel TBC materials that can work at a higher temperature,no single material other than YSZ has all the desired attributes for the TBCs.In this paper,we report the in-situ synthesis of quasi-binary GdNbO_(4)/Gd_(3)NbO_(7)composites based on the simple Gd_(2)O_(3)-Nb_(2)O_(5)binary phase diagram.The fracture toughness of these quasi-binary composites is remarkably enhanced compared with the value predicted by the rule of mixtures because the ferroelastic domain switching is more activated due to the residual stress in the quasi-binary composites,which triggers more crack defections due to the enlarged process zone.Additionally,the Gd_(3)NbO_(7)phase provides a low thermal conductivity due to the substantial chemical inhomogeneity,which diffuses phonons.Gd_(3)NbO_(7)/GdNbO_(4)exhibits a balanced thermal conductivity of 1.6 W/(m·K)at 1073 K and a toughness value of 2.76 MPa·m0.5,and these values are among the best comprehensive properties that have been obtained for new TBC materials.The work demonstrates a feasible approach of designing a new TBC material with balanced properties and can be easily fabricated.

关 键 词：thermal barrier coating(TBC) fracture toughness thermal conductivity residual stress 

分 类 号：TB35[一般工业技术—材料科学与工程]