有机凝胶法低温合成纳米Sr_xBa_(1-x)Nb_2O_6粉体

Low Temperature Preparation of Strontium Barium Niobate Powders by the Aqueous Organic Gel Method

以柠檬酸和乙二胺四乙酸为配位剂与金属离子配位,以水作为溶剂,采用有机凝胶法合成了纳米SrxBa1-xNb2O6(x=0.5)陶瓷粉体.以TG/DTA对金属羧酸盐凝胶的热分解历程进行了分析,以XRD分析了不同煅烧温度下所得产物的相组成.结果表明,在800℃下煅烧2h可获得单一四方钨青铜相SBN粉体.研究了溶液pH值和柠檬酸用量对Sr-Ba-Nb前驱体凝胶稳定性的影响.通过计算Sr-EDTA和Ba-EDTA配合物的条件形成常数Kcf及实验确定获得稳定Sr-Ba-Nb前驱体凝胶的最佳pH=8.

SrxBa1-xNb2O6(x=0.5)ceramic powders were synthesized by the aqueous organic gel routes. The desired metal cations were chelated in a solution by using citric acid and ethylenediaminetertraacetic acid (EDTA)as the chelating agents. The thermal decompostion of the metal carboxylate precursor gels was studied by TG/DTA and the products derived from calcinations of the gels at different temperatures were characterized by XRD and TEM. The results reveal that tetragonal tungsten bronze-type structural SBN with fine particle size can be achieved at 800degreesC. The influences of pH and molar ratio of citric acid: Nb cation on the formation of homogeneous Sr-Ba-Nb precursor gels were also studied. pH=8 used during the preparation of Sr-Ba-Nb precursor gels was determined by calculation of the conditional formation constant K-cf of Sr-EDTA and Ba-EDTA complexes.