Negative Thermal Expansion up to 1000°C of ZrTiO4-Al2TiO5 Ceramics for High-Temperature Applications
High temperature structural ceramics based on Al2TiO5-ZrTiO4 (ZAT) having excellent thermal-shock-resistance were synthesized by a reaction sintering. The ZAT ceramics sintered at 1600oC had a negative thermal expansions up to 1000oC and a much lower thermal expansion coefficient (0.3 ~ 1.3 x 10-6 /K) than that of polycrystalline Al2TiO5 (1.5 x 10-6 /K). These low thermal expansion are apparently due to a combination of microcracking caused by the large thermal expansion anisotropy of the crystal axes of the Al2TiO5 phase. The microstructural degradation of the composites after various thermal treatment for high temperature applications were analyzed by scanning electron microscopy, X-ray diffraction, ultrasonic and dilatometer.
Wei Pan, Jianghong Gong, Chang-Chun Ge and Jing-Feng Li
I. J. Kim et al., "Negative Thermal Expansion up to 1000°C of ZrTiO4-Al2TiO5 Ceramics for High-Temperature Applications", Key Engineering Materials, Vols. 280-283, pp. 1179-1184, 2005