Preparation and thermophysical properties of La2(Zr0.7Ce0.3)2O7 ceramic via sol–gel process

Lanthanum zirconate (La2Zr2O7, LZ) has a very important application for thermal barrier coatings (TBCs) due to its higher sintering-resistance than 8 wt.% yttria stabilized zirconia (8YSZ), and this property could be further improved by the proper addition of ceria. In this paper, the La2(Zr0.7Ce0.3)2O7 (LZ7C3) nanoceramics for potential TBC application were synthesized via sol–gel process. The structure evolution, sintering-resistance and thermophysical properties of the synthesized powders and sintered ceramic bodies were investigated in detail. The XRD and Raman spectroscopy results indicate that LZ7C3 keeps a pyrochlore-type structure throughout the sintering temperature from 1000 to 1500 °C. The nano-sized LZ7C3 shows an excellent thermostability after long-term annealing at 1400 °C. The thermal expansion coefficient and thermal conductivity are also investigated. Compared with LZ and 8YSZ, LZ7C3 exhibits the lowest relative density and the highest sintering-resistance, implying that it is a better potential candidate for TBCs.