화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.89, No.1, 340-342, 2006
Rare-earth zirconate ceramics with fluorite structure for thermal barrier coatings
A series of rare-earth zirconate Ln(2)Zr(2)O(7) ceramics (Ln = Dy, Er, and Yb) with a fluorite structure (F-Ln(2)Zr(2)O(7)) were prepared by pressureless sintering from zirconia and rare-earth oxide powders at 1600 degrees C for 10 h in air. The microstructure experiments were performed by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The thermal conductivity and thermal expansion of these ceramics were evaluated using a steady-state laser heat-flux technique and high-temperature dilatometry, respectively. The XRD and SEM results demonstrate that Ln(2)Zr(2)O(7) ceramics with a single fluorite phase are synthesized and no other phases are found. The results of thermal conductivity show that their thermal conductivities (1.3-1.9 W/(m (.) K), 20 degrees-800 degrees C) are as low as those of the referenced Ln2Zr2O7 ceramics (Ln = La, Nd, Sm, and Gd) with pyrochlore structure (P-Ln(2)Zr(2)O(7)). It is concluded that rare-earth zirconate ceramics with a fluorite structure can be considered as candidate materials for future thermal barrier coatings.