Papers by Keyword: ZrTiO₄

Abstract: Sol-gel technology allows the synthesis of powders and nanoporous materials with a complicated structure and morphology, improving the reactivity of the synthesized material. Nanoparticles of ternary oxide ZrO₂-SiO₂-TiO₂ system have properties ascendant to those of the pure components. In the present work, the powders of the ZrO₂-SiO₂-TiO₂ system were obtained by a sol-gel technology. The powder particles were homogenized with a high energy milling process for 1 or 6 hours. The acquired particles and nanoporous ceramic materials, after sintering at 800 ^OC and 1000 ^OC, were characterized by X-ray diffraction, particle size distribution, compressive strength tests, BET specific surface area and porosity analysis.

Abstract: This paper describes microstructure and leakage current characteristics of ZrTiO4 thin films on ITO/Glass substrate were deposited by sol-gel method with a fix per-heating temperature of 250oC for 30min at various annealing temperatures from 600oC to 800oC for 1 hr. The annealed films were characterized using X-ray diffraction. The surface morphologies of annealed film were examined by atomic force microscopy. The dependence of the microstructure and leakage current characteristics on annealing temperature was also investigated.

Abstract: The low thermal expansion (α25-1100oC = 0.05 ~ 1.6 × 10–6/K) of Al2TiO5 ceramics are apparently due to a combination of grain boundary micro cracking caused by the large thermal expansion anisotropy of the crystal axes of the Al2TiO5 phase. During the reheating run, the individual crystallites expanded at low temperature; thus, the solid volume of the specimen expanded into the micro cracks, where as the macroscopic dimensions remained almost unchanged. As a result, the material expanded very little. The micro cracks closed at higher temperatures. This result is closely related to relatively steeper thermal expansion curves.

Abstract: 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.