高分子薄膜电容式湿敏元件

本文叙述高分子薄膜电容式湿敏元件的研制意义,测湿原理、湿敏元件的构造,感温材料的感湿机理、湿敏元件的性能。性能包括感湿特性,响应特性,温度特性,频率特性,耐湿耐水性,长期稳定性等。湿滞回差小,线性好,响应时间短,温度系数小,稳定性好是所研制的湿敏元件的突出特点。电容式湿敏元件是非常有前途的一类湿敏元件。     

电容式高分子湿敏元件敏感材料的选择

阐述了衡量电容式湿敏元件性能的主要依据,分析了电容式湿敏元件的感湿机理,并从灵敏度、湿滞、响应时间、温度系数、长期稳定性等方面,提出了电容式高分子湿敏元件敏感材料的选择方法。     

一种提高陶瓷湿敏元件稳定性的表面修饰技术

介绍了化学沉淀法制备TiO2粉体的方法，通过掺入高价金属离子变成半导体陶瓷，制成湿敏元件．运用表面修饰技术，对元件进行改性，提高湿敏元件的稳定性．     

TiO_2SnO_2系新型湿敏元件的研制

本文提出了一种新型TiO_2-SnO_2系湿敏元件.文中介绍了该器件的主要结构工艺,对感湿机理进行了探讨,并研究其特性.研究结果表明,这种湿敏器件具有良好的湿敏特性,制造工艺简单、成本低等特点.     

铁酸镧与高分子复合材料湿敏元件特性分析

采用纳米铁酸镧与高分子复合材料制成湿敏元件。研究了复合材料和湿敏元件的制作,测试讨论了灵敏度、湿滞、电容特性、阻抗特性、响应 恢复时间等湿度敏感特性。结果表明:元件的灵敏度较高、湿滞较小,元件的电容值和阻抗值随频率与相对湿度而变化。     

降低高分子电容式湿敏元件湿滞的实验研究

针对高分子电容式湿敏元件的湿滞无法通过后续电路完全实现补偿的问题,提出了从高分子电容式湿敏元件本身降低湿滞的方法。主要从制作工艺、湿敏材料的选择两方面进行了实验验证,并对制作完成的高分子电容式湿敏元件进行性能测试与数据分析。实验结果表明：通过控制制作工艺和对湿敏材料进行改性可以降低湿滞,湿滞优于1.5%RH。采用该方法制作的湿敏元件无需再次通过后续电路进行湿滞补偿。     

以石墨粉为造孔剂制成的多 孔湿敏陶瓷及其特性分析

本文报道的钴铁尖晶石多孔湿敏陶瓷,具有电阻率低,电阻和相对湿度呈线性关系的特点。该材料制成的湿敏元件不需要加热清洗,性能稳定。以石墨粉为造孔剂制成多孔湿敏陶瓷,可以提高湿敏元件的湿度灵敏度,并且有利于改进湿敏元件的长期稳定性。最后,讨论了石墨的钝化作用。     

水热腐蚀铁钝化多孔硅的湿敏特性研究

采用水热腐蚀铁钝化法在单晶硅片上生长铁钝化多孔硅(IPS)薄膜,以IPS为感湿介质制成湿敏元件。在不同湿度环境以及测试频率下,测出其电容值,得到了IPS的湿敏特性曲线。研究发现,当相对湿度从11%RH逐渐增加到95%RH的过程中,在测试频率为100Hz时,IPS湿敏元件的电容值增大幅度达1500%,电容响应时间在升湿过程和脱湿过程分别为15s和5s,并且IPS湿敏元件的温度系数在15℃到35℃的范围内较小。结果表明:IPS湿敏元件的特性包括灵敏度、响应时间以及温度系数等均优于多孔硅(PS)湿敏元件的特性。     

超微细TiO_2湿敏材料研究

介绍了以化学沉淀法制备超微细TiO2 粉体方法 ,通过对材料半导化改性 ,使TiO2 由绝缘体变成半导体 ,并具有感湿特性 ,通过表面修饰技术 ,改善了湿敏元件的阻 -湿特性及长期稳定性。     

新型陶瓷湿敏元件的性能研究

本文介绍了用金属氧化物陶恣材料制成的湿敏元件及其感湿特性，对陶恣材料的结构以及元件的感湿特性与陶材料结构的关系进行了初步的探讨。     

温湿度对SnO2基CO气体传感器敏感特性的影响

采用溶胶-凝胶法制备了纳米SnO2粉体及Pd掺杂浓度比分别为0.2 mol%、2 mol%1、0 mol%的三种掺杂粉体。以制得的粉体作为敏感材料,制成陶瓷微热板式CO气体传感器。在自行搭建的气体测试平台上,测试了各传感器在不同环境温湿度条件下对CO的响应,研究了Pd掺杂浓度对传感器湿度稳定性的影响,探讨了湿度影响传感器灵敏度的机理。实验结果表明:0.2 mol%Pd掺杂器件在不同湿度条件下灵敏度离散度由掺杂前的20.5%降低至8.63%,有效提高了传感器的湿度稳定性。10 mol%Pd掺杂器件在湿度大于50%相对湿度时,对20×10-6 CO出现反常响应,在还原气体CO出现时气敏膜电导减小。     

基于集成气敏传感器阵列的电子鼻系统环境响应特性分析

基于集成气敏传感器阵列和多传感器信息融合技术的电子鼻系统 ,可用于气体 /气味的定性定量识别 .在实际应用中 ,被识别样本的浓度、样本环境的温度和湿度参数等都对电子鼻系统的响应特性有较大的影响 .本文分别利用纯净空气及乙醇或葡萄酒作为载气及分析样本 ,对电子鼻系统响应特性与气敏传感器工作温度以及样本温度、环境湿度、样本浓度间的依赖关系进行了实验分析 ,并分别给出了它们间依赖关系的实验结果 .     

Study on humidity sensing property based on Li-doped mesoporous silica MCM-41

Pure and LiCl-doped mesoporous silica MCM-41 with different doping concentrations (1, 2, 5, 10 and 15 wt.%) have been prepared. XRD, IR spectra and SEM characterized the materials. These different characterization results suggest that these materials have the similar mesoporous structure. A resistive-type humidity sensor was fabricated on a ceramic substrate with Ag–Pd interdigital electrodes. The humidity sensing properties of the sensors were investigated at different frequencies. The studies revealed that the LiCl-doping was beneficial for improving the humidity sensing properties of the samples. The sample with 2 wt.% LiCl dopant has the best sensing properties to humidity. Finally, a possible mechanism is suggested to explain the humidity-sensitive properties.     

Properties of humidity sensing ZnO nanorods-base sensor fabricated by screen-printing

The humidity sensitive characteristics of a sensor fabricated from flower-like ZnO nanorods by screen-printing on a ceramic substrate with Ag–Pd interdigital electrodes have been investigated. The sensor shows high humidity sensitivity, rapid response and recovery, small hysteresis, and good stability. It is found that the impedance of the sensor decreases by about five orders of magnitude with increasing relative humidity (RH) from 11 to 95%. The response and recovery time of the sensor is about 5 and 10 s, respectively. These results indicate that the flower-like ZnO nanorods can be used in fabricating high-performance humidity sensors.     

Highly stable and sensitive humidity sensors based on quartz crystal microbalance coated with bacterial cellulose membrane

A novel highly stable and sensitive humidity sensor based on bacterial cellulose (BC) coated quartz crystal microbalance (QCM) has been successfully fabricated. The results showed that the sensors possessed good sensing characteristics by increasing more than two orders of magnitude with increasing relative humidity (RH) from 5 to 97%, and the Log(Δf) showed good linearity (20-97% RH). The sensitivity of sensors coated with BC membranes was four times higher than that of the corresponding cellulose membranes at 97% RH. In addition, the sensor sensitivity is greatly enhanced by increasing the coating load of the BC membranes with more absorption sites in the sensing membranes. Moreover, the experimental results prove that the resultant sensors exhibited a good reversible behavior and good long term stability. Herein, not only a novel and low-cost humidity sensor material was exploited, but also a new application area for BC nanofibrous membranes was opened up.     

Humidity sensor based on LiCl-doped ZnO electrospun nanofibers

The humidity sensitive characteristics of sensors fabricated from pure ZnO nanofibers and LiCl-doped ZnO composite fibers by screen-printing on ceramic substrates with carbon interdigital electrodes have been investigated. The best result is obtained for 1.2 wt% LiCl-doped sample, which exhibits high humidity sensitivity, rapid response and recovery, small hysteresis, excellent linearity, and good reproducibility. The impedance of the sensor varies more than four orders of magnitude during the whole relative humidity (RH) from 11 to 95%. The response time and recovery time of the sensor is about 3 and 6 s, respectively. These results make our product a good candidate in fabricating high performance humidity sensors.     

陶瓷湿敏元件的稳定化研究

本文对研制的 Nasicon系和 Zr O2 系陶瓷湿敏材料和湿度传感器的稳定化进行了分析研究 .采用直流电导法判定 Nasicon系和 Zr O2 系湿敏材料的导电机制分别是离子电导为主的离子 -电子混合电导和离子电导 .施加交直流电场能激活材料的离子电导 .提出了适用于离子型电导为主湿敏材料的状态模型 .湿度传感器经常处于交流电场 (工作电压 )下可锁定其活化状态 ,是保持湿度传感器稳定化的有效方法     

多孔Al_2O_3薄膜感湿材料的湿敏特性研究

通过对阳极氧化多孔Al2 O3 薄膜感湿材料的制备工艺及其电容湿敏特性进行研究 ,将阳极氧化参数对多孔Al2 O3 薄膜的结构和形态的影响与多孔Al2 O3 薄膜作为湿度传感器感湿材料的湿敏特性联系起来进行分析 ,为优化制备工艺参数提供更充分的实验数据 ,使新型多孔Al2 O3 薄膜湿度传感器具有更好的感湿特性。     

Capacitive humidity sensors based on a newly designed interdigitated electrode structure

This paper presents a study of capacitive humidity sensors constructed based on a newly designed interdigitated electrode (IDE) structure with a polyimide (PI) sensing layer fabricated using micro-electro-mechanical system (MEMS) technology. The humidity sensors use an IDE with increased height, formed by the surface micromachining of a silicon substrate. The fabricated sensors showed higher sensitivity in variable ambient relative humidity (RH) when compared with the humidity sensors of a conventional IDE since the horizontal electric field lines, generated between the thick electrodes, are confined to the PI sensing layer. The effect of the thickness of the PI layer was also investigated. The fabricated sensors with a 4-μm-thick PI layer showed a higher sensitivity of 37.1 fF/%RH when compared with those of a 2- and 3-μm-thick PI layers, indicating that the properties of the sensors depend on the thickness of the PI layer. This is because the amount of the fringing electric field lines passing through the PI is determined by the PI thickness. In addition, the sensor with the 4-μm-thick PI showed very slight hysteresis with a maximum of 2.87%RH and displayed high stability with a variation range of 0.06 pF.     

高分子共聚物类湿敏元件的湿敏特性数据处理

文章通过测定季铵化聚苯乙烯共聚物类湿敏元件的湿敏特性，根据Arrhenius关系和大量测试数据的分析，导出了该湿敏元件的电阻随着相对湿度变化的半经验公式，并通过实例应用该半经验公式。