半导陶瓷湿度传感器的阻抗—湿度特性

Impedance-Humidity Characteristics of Semiconducting Ceramic Moisture Sensors

用二氧化锆、二氧化硅、磷酸和其它掺杂剂制作各种半导瓷湿度传感器。电导的加强是依靠水的吸附和毛细凝聚。随着相对湿度逐步从5％增大到100％,在20℃和1kHz时,阻抗由2×10~8Ω减小到2×10~3Ω。电阻随湿度改变的响应时间在5s以下,为了降低多元氧化物半导瓷的阻抗,研究了多孔瓷体中掺杂纯金属或金属氧化物的效果,对一种最简单的制作半导瓷湿度传感器的方法作了具体介绍。推导了半导瓷湿度传感器的通用的阻抗—湿度特性方程式,并且用以计算一些实际样品的阻抗—湿度特性曲线,获得理论结果同实验测量之间互相一致。

Zirconia is used as a major raw material together with silica, phosphoric acid and other doping agems to prepare variour semiconducting ceramic moisture sensors. The admittance is enhanced by the adsorption and the capillary condensation of water. With changing the humidity step by step form 5%r.h. to 100%r.h., the impedance changes from 2 × 108Ωto 2 × 103Ω at 1Hz and 20 ℃ . The response times of the resistance to the humidity changes are 5 second or below. In order to decrease the impedance of semiconducting ceramic using polynary oxides, the results of doping a pure metal or a metal oxide respectively into the porous ceramic oxides are studied. A kind of the simplest method to manufacture the semiconducting ceramic moisture sensors is introduced in the concrete. A general impedance- humidity characteristic equation of semiconducting ceramic moisture sensor has been derived, and applied to calculate the impedance- humidity characteristic plots of some true samples. An agreement between theoretical result and experimental measurement has been obtained.