钛掺杂的α-Fe_2O_3-K_2O纳米湿敏陶瓷结构与性能研究

Structure and Humidity-sensitive Properties of TiO_2-doped α-Fe_2O_3-K_2O Nanometer-sized Ceramics

采用硬脂酸凝胶法新工艺在α－Fe2O3－K2O复合体系中掺入TiO2.XRD、BET比表面吸附、Archimede排水法等手段对掺钛α－Fe2O3－K2O纳米陶瓷分析表征结果表明，适量掺杂TiO2，材料仍保持α－Fe2O3的刚玉结构，且具有很高的热稳定性，但抑制了主晶相晶粒成长，增大了材料比表面积及孔隙率．电性能及湿敏特性测试结果表明，适量掺杂TiO2，降低了材料固有电阻，显著减小了材料湿滞；认为钛掺杂使材料晶粒细化；从而使K+更加分散地沉积在α－Fe2O3晶粒表面非晶壳层中，是改善材料湿滞的主要原因．

TiO2 waJs doped in α-Fe2O3-K2O composite system by a stearic acid-gel method. Phase composition , grain size, lattice distortion , specific surface area, porosity and thermal stability of TiO2-doped α-Fe2O3-K2O nanometer-sized ceramics were investigated by X-ray diffraction ,BET specific surface absorption and Archimede replacement water methods. The results show that doping of a little amount of TiO2 restrains the formation of KFe11O17 and β-K2O , retards the growth of α-Fe2O3 grain , makes α-Fe2O3 lattice distortion , improves its thermal stability and keeps its phase structure of corundum as α-Fe2O3. Furthermore , the relationship between TiO2 doped amount and inner electrical resistance , resistance-humidity chaxacteristic and humidity hysteresis of the various TiO2-doped α-Fe2O3-K2O system were also studied. It shows that K+ possibly more dispersedly exists in the amorphous surface shell layer of α-Fe2O3 after doping TiO2, and that is the main reason of humidity hysteresis being decreased.