溶胶-凝胶法合成(Na_(0.5)Bi_(0.5))TiO_3微粉

Synthesis of (Bi_(0.5)Na_(0.5))TiO_3 Ultrafine-Powder by Sol-Gel Method

以钛酸四丁酯、硝酸铋、醋酸钠和冰醋酸为原料，利用溶胶一凝胶工艺得到透明凝胶，经干燥后煅烧成（Na0.5Bi0.5）TiO3微粉。通过对溶胶体系水／醇盐的摩尔比、初始pH值及胶凝温度对（Na0.5Bi0.5）TiO3凝胶体系溶胶．凝胶形成过程影响的研究，发现彬醇盐比R在35≤R≤60，pH在2．2-3．5，反应温度在40-60℃时，能够得到透明的溶胶；通过TG-DTA、SEM、X-ray等分析手段对（Na0.5Bi0.5）TiO3粉体进行测试，表明在650℃合成1h可以得到单一钙钛矿（Na0.5Bi0.5）TiO3晶体；采用TEM对（Na0.5Bi0.5）TiO3干凝胶粉体分析其粒径大小约为10nm。

The clear and transparent gels of sodium-bismuth titanate can be prepared using tetrabutyl titanate, bismuth nitrate pentahydrate, sodium acetate, and acetic acid as starting materials by sol-gel technology＇and the （Na0.5Bi0.5）TiO3 ultrafine-powders were produced after the dry gels were calcined. Through the research over the influence of initial pH value of sol, a mole ratio of water and alkoxide, temperature of sols of the formation of sol-gel, it proves that the clear and transparent sols are attained, with the initial pH value of 2.2-3.5, a mole ratio of water to alkoxide of 35-60, and the temperature of 40-60℃. The characteritics of （ Na0.5 Bi0.5 ） TiO3 powder were analyzed by means of thermo-gravimetric analysis （TG）, differential thermal analysis （DTA）, SEM, and X-ray diffraction （XRD）, it shows that pure single phase （Na0.5Bi0.5）TiO3 powders could be obtained at 650℃ for lh. The particle size of the dry-gel powders examined by TEM is about 10nm.