MnWO_4-Li_2WO_4系厚膜湿敏元件的性能

Properties of MnWO_4-Li_2WO_4 system thick film humidity sensors

本文采用溶胶凝胶法制备WO3纳米粉体,再与MnCO3固相反应合成MnWO4,掺杂得到不同配比的MnWO4-Li2WO4湿敏材料,通过丝网印刷工艺制备厚膜湿敏元件。实验研究表明在适当的工艺条件下,MnWO4中掺杂30mol%Li2WO4的材料,所制备的元件具有低湿电阻小、灵敏度高、响应速度快、湿滞小的特点,这些特点为产品的实用化提供了有利条件。SEM照片和复阻抗分析表明,该方法制备的材料具有纳米晶粒和优良的晶界微结构,是改善元件性能的重要原因。

Thick film humidity sensors were prepared by the screen -printing technique starting from Mn- WO4 -Li2WO4 system powders, the MnWO4 obtained by solid state reaction with the MnCO3 and WO3 which was prepared by sol -gel method. The experiment results show that the prepared sensor by MnWO4 doping Li2WO4 of 30mol% has several main features such as the lower resistance at lower humidity, high sensitivity, quick response and small humidity hysteresis. These features are important to the practical use of this material system. The SEM photograph and complex impedance analysis indicate that the thick film humidity sensor has a better microstructure of the nanometer crystal grain and crystal boundary which is the important factor influencing the humidity sensing performance.