摘要
采用硬脂酸凝胶法这种化学新工艺制备了α Fe2 O3 TiO2 K2 O复合氧化物纳米湿敏陶瓷元件 ;研究了该元件在不同湿度下的复阻抗谱 ,并建立相应的模拟等效电路 ;材料晶粒电阻、晶界电阻等特征参数计算结果表明 ,晶粒电阻基本不随湿度变化 ,晶界电阻随湿度升高而降低 .从晶界电阻角度探讨了本系材料的湿敏导电机制 ,低湿阶段导电载流子为电子和自由H+,自由H+以氢桥键过渡态机制迁移 ,中、高湿阶段导电载流子以H3O+为主 .
Composite oxide humidity-sensitive ceramics α Fe 2O 3 TiO 2 K 2O was prepared by stearic acid gel technology.The complex impedance of the prepared ceramic sensor was studied under different relative humidities.Correspondingly,the appropriate simulative equivalent circuit was set up.By terms of those,the grain resistance and grain boundary resistance were calculated.the results showed that with increasing of relative humidity,the grain resistance was basically changeless,and the grain boundary resistance decreased.Furthermore,the humidity-sensitive mechanism of the prepared ceramic sensor was discussed by means of the method of complex impedance.It is proposed that(1)the grain boundary is the main humidity-sensitive part,(2)the conductive carriers of the prepared humidity sensor are electron and free proton(H +)under low humidity region,free H + probably migrated according to hydrogen bridge bond transitional state mechanism,and the carrier is mainly H 3O + under middle and high humidity region.
基金
国家自然科学基金项目资助课题(29571026)
