부산대학교 도서관

In this paper, ([Gd.sub.1-x][Y.sub.x])Ta[O.sub.4] ceramics have been fabricated by solid-phase synthesis reaction. Each sample was found to crystallize in a monoclinic phase by X-ray diffraction (XRD). The properties of ([Gd.sub.1-x][Y.sub.x])Ta[O.sub.4] were optimized by adjusting the ratio of Gd/Y. ([Gd.sub.1- x][Y.sub.x])Ta[O.sub.4] had a low high-temperature thermal conductivity (1.37-2.05 W*[m.sup.-1]*[K.sup.-1]), which was regulated by lattice imperfections. The phase transition temperature of the ([Gd.sub.1-x][Y.sub.x])Ta[O.sub.4] ceramics was higher than 1500 [degrees]C. Moreover, the linear thermal expansion coefficients (TECs) were 10.5x[10.sup.-6] [K.sup.-1] (1200 [degrees]C), which was not inferior to yttria-stabilized zirconia (YSZ) (11x[10.sup.-6] [K.sup.-1], 1200 [degrees]C). ([Gd.sub.1- x][Y.sub.x])Ta[O.sub.4] had anisotropic thermal expansion. Therefore, controlling preferred orientation could minimize the TEC mismatch when ([Gd.sub.1-x][Y.sub.x])Ta[O.sub.4] coatings were deposited on different substrates as thermal barrier coatings (TBCs). Based on their excellent properties, it is believed that the ([Gd.sub.1-x][Y.sub.x])Ta[O.sub.4] ceramics will become the next generation of high-temperature thermal protective coatings. Keywords: thermal barrier coatings (TBCs); thermal conductivity; high-temperature phase stability; high-temperature X-ray diffraction (XRD); anisotropic thermal expansion
1 Introduction Thermal barrier coatings (TBCs) are regarded as components of diesel generators, aero-engines, and high-speed aircraft for improved efficiency and power [1,2]. At present, the most widely used TBC [...]