溶胶-凝胶法制备BST/MgO复合粉体晶化过程研究  

Research on the Crystallization Procedure of BST/MgO Composite Powder Prepared by the Sol-Gel Method

作　　者：杨觉明[1] 范琳[1] 刘秀兰[1] 

机构地区：[1]西安工业大学材料与化工学院,西安710032

出　　处：《西安工业大学学报》2007年第5期451-455,共5页Journal of Xi’an Technological University

摘　　要：为降低钛酸钡锶BST／MgO陶瓷烧结温度，减小BST晶粒尺寸，采用溶胶一凝胶法制备BST／MgO复合粉体，DTA／TGA，FT—IR，XRD，TEM和SEM分析BST／MgO干凝胶的晶化过程．结果表明，采用溶胶一凝胶法制备出包裹MgO粉体的BST凝胶，凝胶经干燥、预烧得到BST／MgO复合粉体．凝胶干燥后形成含Ba抖，Sr抖的非晶态干凝胶，干凝胶在晶化过程中会形成BaCO3和SrCO3，它们与TiO2反应形成钙钛矿晶型结构的BST．BST的钙钛矿结构主要在550-650℃形成，粉体在700℃预烧后基本完全晶化，得到包含BST和MgO两相的复合氧化物粉体，其中BST晶粒大小约20nm，MgO晶粒大小〉0．1μm．粉体经冷等静压成型和1300℃无压烧结制得BST晶粒为3～5μm的BST／MgO陶瓷，烧结温度比普通固相反应烧结温度低约150℃．In this paper, BST/MgO composite powder was prepared by Sol-Gel method for reducing the sintering temperature and the grain size, and the crystallization process of the powder was studied by using DTA/TGA, FT-IR, XRD, TEM. The results show that MgO powder is enwrapped by the BST sol during the Sol-Gel process. During the process from BST xerogel to BST ceramic, BaCO3 and SrCO3 formed firstly, and then BaCO3 and SrCO3 decomposed and reacted chemically with TiO2 to form BST. The perovskite structure of BST formed between 550℃ and 650℃. The powder completely transited to crystal at 700 ℃. By presintering at 700℃, BST phase and MgO phase are found in the composite powder. The grain sizes of BST and MgO are about 20 nm and larger than 0.1μm, respectively. After molding by cold isotonic press and no press sintering at 1 300℃, BST/MgO ceramic can be prepared. The sintering temperature of BST/MgO ceramic is lower about 150℃ than the sintering temperature of general solid reaction.

关 键 词：溶胶-凝胶法 晶化过程 复合粉体 BST陶瓷 

分 类 号：TB383.3[一般工业技术—材料科学与工程]