Electrical properties of sintered Zr(RPO4)2radical dotnH2O (R=Li, Na, K, Rb and Cs) in a humid atmosphere

Five humidity sensor elements using porous ceramics prepared by sintered Zr(RPO4)2radical dotnH2O (R=Li, Na, K, Rb and Cs) at 1000 °C were produced and the effect of microstructure on the humidity sensitivity was investigated. A layered structure was retained for the sintered samples (R=Na, K, Rb and Cs). For sintered Zr(RPO4)2·nH2O (R=Na, K, Rb and Cs), the impedance in the low-humidity region was about 1×108 Ω·cm and changed about four orders in the humidity region of 0–90% RH. The response time of sintered Zr(RPO4)2radical dotnH2O (R=Li, K, Rb and Cs) for humidity change was about three minutes with a quick change of humidity from 60 to 90% RH and vice versa. Change in humidity sensitivity for all the sintered Zr(RPO4)2radical dotnH2O samples was less than 5% RH for 200 days in room conditions.