Synthesis of potassium sodium niobate powders using an EDTA/citrate complexing sol-gel method  

作　　者：Yang Cao Kongjun Zhu Hongjuan Zheng Jinhao Qiu Honghui Gu 

机构地区：[1]State Key Laboratory of Mechanics and Control of Mechanical Structures,Nanjing University of Aeronautics and Astronautics

出　　处：《Particuology》2012年第6期777-782,共6页颗粒学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(NSFC No.51172108);Program for Changjiang Scholars and Innovative Research Teams in Universities(IRT0968);Program for New Century Excellent Talents in Universities(NCET10-0070);a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions;Nanjing University of Aeronautics and Astronautics Research Fund for Fundamental Research(NJ2010010,NZ2010001)

摘　　要：Potassium sodium niobate （KNN） powders were synthesized by a modified sol-gel method, using as starting chemicals potassium carbonate, sodium carbonate, and niobium hydroxide, and, as esterification and chelating agents, respectively, ethylene glycol （EG） and ethylene diamine tetraacetic acid （EDTA）/citrate. The effects of citric acid （CA）, EG, and EDTA on the stability of the precursor sol were systemically inves-tigated. The powders and gels were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis-differential scanning calorimetry （TGA-DSC）. The results indicated that a stable precursor sol was formed when n（CA）：n（Mn＋）= 3：1, n（EDTA）：n（NH4OH） = 1：3.5, and n（CA）：n（EG） = 1：2. The xerogel was calcined at 500-950 ℃ to prepare the KNN powder. Pure KNN perovskite phase with a cube-like structure was synthesized at 850 ℃ from the precursor sol for a K/Na molar ratio of 1.2. The formation mechanism of the KNN perovskite phase was also discussed.Potassium sodium niobate （KNN） powders were synthesized by a modified sol-gel method, using as starting chemicals potassium carbonate, sodium carbonate, and niobium hydroxide, and, as esterification and chelating agents, respectively, ethylene glycol （EG） and ethylene diamine tetraacetic acid （EDTA）/citrate. The effects of citric acid （CA）, EG, and EDTA on the stability of the precursor sol were systemically inves-tigated. The powders and gels were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis-differential scanning calorimetry （TGA-DSC）. The results indicated that a stable precursor sol was formed when n（CA）：n（Mn＋）= 3：1, n（EDTA）：n（NH4OH） = 1：3.5, and n（CA）：n（EG） = 1：2. The xerogel was calcined at 500-950 ℃ to prepare the KNN powder. Pure KNN perovskite phase with a cube-like structure was synthesized at 850 ℃ from the precursor sol for a K/Na molar ratio of 1.2. The formation mechanism of the KNN perovskite phase was also discussed.

关 键 词：（ K0.5 Na0.5 ）NbO3EDTA/citrate Sol-gelSubmicron powder 

分 类 号：TB383.3[一般工业技术—材料科学与工程]