The Thermal Expansion of Lanthanum Zirconate Ceramics

The high-temperature behavior of lanthanum zirconate ceramics was studied depending on the conditions of La2Zr2O7 synthesis and sintering. Lanthanum zirconate was obtained by solid-phase synthesis, the ceramics were sintered in the temperature range of 1500–1550°C at different holding times. Thermal expansion and shrinkage activity of ceramics were studied by dilatometric analysis. Linear thermal expansion coefficients (LTECs) were determined in the temperature range of 200–1200°C during heating and cooling. The LTEC of the obtained ceramics is 9.1 × 10–6 1/K, which is significantly less than the LTEC of tetragonal zirconium dioxide doped with yttria (YSZ), 13.5 × 10–6 1/K. The LTEC decreases as the density of the ceramics increases. The microhardness of synthesized ceramics is 6.3 GPa.