Solid electrolyte film humidity sensor

An impedance-type, solid state thick-film humidity sensor based on a NASICON-type proton conductor, HZr2(PO4)(3) has been developed and tested in a wide range of temperature (25-250 degrees C) and relative humidity (2-100%). The film sensor showed enhanced sensitivity compared to the bulk sensor and fast and reproducible response (similar to 10-15 s), even at ambient temperature. Long-term tests of the film humidity sensors show relatively good agreement with the commercial humidity sensor, OMEGA-RH-20C at room temperature, and excellent agreement with commercial Vaisala-sensor at higher temperatures over several weeks. The sensor signal is dependent on the thickness, as well as on the microstructure of the film. (C) 1998 Published by Elsevier Science B.V. All rights reserved.