Humidity Sensors of Mixed Metal Oxides

For the purpose of developing new functional materials, mixed metal oxides were searched as ceramic humidity sensors. The present investigation was conducted to clarify the influence of chemical and physical properties of ceramic material on its electrical conductivity in the presence of adsorbed water. The infrared spectral results of the adsorption structure of water showed that the humidity-impedance characteristics of elements at room temperature was caused by physisorbed water. It has become apparent that the impedance of ceramics are dependent on the composition, degree of sintering, and adsorption amount of water. Good humidity sensors are expected to be obtained by controlling bulk properties, surface area, microstructure, and sintering of ceramic materials