纳米钛酸钡粉体的制备和烧结动力学研究

Synthesis of nano-sized barium titanate powders and study on sintering kinetic

以四氯化钛、八水合氢氧化钡和氨水为原料,首先制备出氢氧化钛凝胶,然后以乙醇为溶剂,采用两步沉淀法在低温常压下合成了立方相纳米钛酸钡粉体。研究了反应温度、反应物浓度和反应时间对粉体物相和粒径的影响,利用XRD和TEM对粉体进行了表征。实验结果表明,在低于80℃的反应温度下可以制备出粒径〈20nm、结晶性能良好且形貌规则的纳米钛酸钡粉体。此外,以合成的粉体为原料,以热膨胀仪为测试手段,对钛酸钡陶瓷的烧结动力学进行了研究。结果表明,陶瓷的烧结温度为1150~1250℃,在1250℃的烧结温度下保温2h,陶瓷坯体的相对密度约93%,室温介电常数约4020。

Two-step precipitation route was developed to synthesize nano-sized BaTiO3 powders with cubic phase structure at low temperature and under ambient pressure, using TiCl4, Ba（OH）2·8HzO and NH3·H2O as raw materials. During the process, titanium hydroxides gel was obtained firstly and then reacted with barium hydroxide, with ethanol as reaction medium. The influences of reaction temperature, reactant concentration and reaction time on phase composition and particle size were studied, and the as-prepared powders were character- ized by XRD and TEM. The results show that well-crystalline BaTiO3 powders with particle size smaller than 20nm can be obtained at temperature lower than 80℃. In addition, using as-prepared powders, the characteristics of sintering kinetic curves of BaTiO3 ceramic were studied by means of a thermal dilatometer. The results confirm that sintering temperature was 1150-1250℃ and the relative density of ceramic sintered at 1250℃ for 2h was about 93% with dielectric constant evaluated 4020 at room temperature.