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无机材料学报

无机材料学报

• 研究论文 • 上一篇    下一篇

掺镧改性钛酸钡湿敏陶瓷元件

王智民1; 韩基新1; 刘静波1,2   

  1. 1. 黑龙江大学化学化工学院, 哈尔滨150080; 2. 北京科技大学材料科学与工程学院, 北京 100083
  • 收稿日期:2001-09-17 修回日期:2001-11-22 出版日期:2002-11-20 网络出版日期:2002-11-20

Preparation Property and Structure of La3+-doped Barium Titanate Humidity Sensing Ceramic Element

WANG Zhi-Min1; HAN Ji-Xin1; LIU Jing-Bo1,2   

  1. 1. Collge of Chemistry and Chemical Engineering; Heilongjiang University; Harbin 150080; China; 2. Material Science and Engineering Department; University of Science and Technology Beijing; Beijing 100083; China
  • Received:2001-09-17 Revised:2001-11-22 Published:2002-11-20 Online:2002-11-20

PDF (PC)

899

被引次数

22

摘要： 以La(OAc)3、Ba(OAc)2、Ti(OnBu)4为起始物, 采用共溶-水凝胶法经陈化获得湿凝胶, 干燥后制得干凝胶, 研磨过筛和埋渗电极、加压成
型为素坯, 经不同温度和保温时间烧结, 制得掺镧LaxBa1-xTiO3陶?瓷传感元件系列 (x=0.00, 0.05, 0.10, 0.20, 0.30), 测试其阻-湿特
性, 从中获得了具有良好特性参数的湿敏陶瓷及其主要工艺条件(x=0.10, 1350℃/1h), 阻-湿特性在工作湿度范围内(相对湿度RH=32.8%～93.6%)的平均灵敏度S=5×104kΩ/RH(%), 线性相关因子r=0.998, 响应时间τ=110s, 湿滞低于4%, 湿敏选择性良好
: 对H2, CH4, CH2=CH2, CH3CH=CH2, CO, C6H6 和CH3CH2OH(g)七种气体具有抗干扰性能. 应用SEM, AFM及XRF对陶瓷的显微结构和
元素含量进行测定, 确定了陶瓷的显微组织, 晶粒尺寸, 晶相结构, 表面粗糙度和全元素分析. 讨论了掺镧改性的可能机理: La3+不等价取代Ba2+, 引起Ti4+捕获一个自由电子而变价为Ti3+, 该?电子在适宜的陶瓷显微结构下受水分子影响易于进入导带, 使掺镧钛酸钡得以
半导化; 半径较小的La3+取代半径较大的Ba2+, 则降低四方晶相的晶格畸变度δ, 即晶轴比c/a变小, 使四方晶格的不对称性及各向
异性?降低, 从而减少陶瓷烧结后冷却过程中内应力引起的破裂.

关键词: 掺镧改性钛酸钡LaxBa1-xTiO3, 陶瓷元件, 湿敏, 显微结构表征

Abstract: Sol precursors were prepared by the cosolubilized hydrousgel process using titanium butoxide and lanthanum
acetate as well as barium acetate. After condensation and drying, the wet gel and dry gel were obtained respectively. Dry gel ground and screened
was pressed into disc and sintered at different temperatures for holding different time to fabricate ceramic sensors. The measurement of humidity
sensitivity and gas/alcoholic sensitivity (seven kinds of gases H2, CH4, CH2=CH2, CH3CH=CH2, CO, C6H6 and gaseous CH3CH2OH) of these sensors were performed. The humidity sensor displays high sensitivity: S=5×104kΩ/RH(%) (relative
humidity RH=32.8%～93.6%); good linearity: r=0.998; minimum humidity hysteresis: <4%; response time: τ=110s; and fine selectivity: sensitivity-less to above seven kinds of gases. The microstructure was characterized by SEM, AFM and XRF to confirm the
morphology, perovskite phase and surface roughness and whole element analysis. The mechanism of lanthanum modification was discussed that
titanium ion Ti4+ can capture a free electron. It is easy for this electron to jump into the conduct band due to non-equivalent substitution
of Ba2+ by rare earth ion La3+.

Key words: modification of La3+-doped barium titanate （LaxBa1-x ceramic element, humidity sensitivity, microstructure characterization

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