摘要
采用溶胶 凝胶工艺在α Fe2 O3 K2 O复合体系中掺入SiO2 .XRD、BET比表面吸附、Archimede排水法等对α Fe2 O3 K2 O SiO2 陶瓷表征结果表明 ,适量掺杂SiO2 ,材料仍以刚玉结构的α Fe2 O3为主晶相 ,但抑制了主晶相晶粒粗化 ,增大了材料比表面积及孔隙率 .湿敏性能测试发现 ,掺杂摩尔分数 6%的SiO2 ,可获得全湿区范围内阻—湿特性曲线线性关系良好、灵敏度适中、湿滞小、稳定性较高的新型湿敏材料 .其中 ,K+被吸收分散在主晶相晶界硅玻璃相中是改善材料湿滞效应及性能稳定性的主要原因 .
SiO 2 was doped in α Fe 2O 3 K 2O composite system by Sol Gel technique. Phase composition, grain size, lattice distortion ratio, specific surface area, and porosity of SiO 2 doped α Fe 2O 3 K 2O ceramics had been investigated by X ray diffraction, specific surface area absorption (BET) and Archimede replacement water method. The results showed that doping of a little amount of SiO 2 restrained the formation of KFe 11 O 17 and β K 2O,retarded the growth of α Fe 2O 3 grains , made the α Fe 2O 3 lattice distort, and still had a phase structure of corundum as α Fe 2O 3. Furthermore, the relationship between SiO 2 doped amount and humidity sensitivity characteristics of the various SiO 2 doped α Fe 2O 3 K 2O ceramics had also been studied. The results showed that α Fe 2O 3 ceramics contained 6% SiO 2 and exhibited an ideal humidity sensitive characteristics, a good stability and small hysteresis. It is proposed that K + possibly disperses in the silica amorphous glassy layer on α Fe 2O 3 grains, and that is the main reason of humidity hysteresis decrease and a good stability.
基金
国家自然科学基金!项目资助课题 (NO .2 9571 0 2 6)
关键词
溶胶凝胶
掺杂
α-F3O2
陶瓷
SIO2
湿敏材料
Sol Gel
doping
α hemetite
humidity sensitive sensor
humidity hysteresis
stability
