Principles and Applications of Ceramic Humidity Sensors

摘要

This paper presents a brief review of the state of the art in humidity and gas ceramic sensors R&D; italso describes the principle, fabrication and application of the humidity-sensitive Si-doped a-hematite(α-Fe2O3) sintered compacts.The humidity signal response is characterized by volt-amperometric and impedance spectroscopytechniques in the 0-97% relative humidity (RH) range. The response time of the sensor is evaluatedby 0-60% RH variations. Experimental techniques used to measure the hysteresis, drift, and aging ofthe humidity setasor are presented and the results are discussed. The CO sensitivity is investigated byactivating the sensor in the 350-450℃ temperature range.A humidity-meter prototype, based on the α-Fe2O3ceramic compact is described, and its electronicsand features are presented in this paper.