共查询到17条相似文献,搜索用时 500 毫秒
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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。 相似文献
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制备了电阻式纳米钛酸钡湿敏元件,测试了元件的阻抗、电容,以及介电损耗特性.测试频率对元件的阻抗-相对湿度特性曲线影响较大,特别是低湿范围.100 Hz时曲线的线性度最好.元件的电容在低频范围随相对湿度的升高而增大,但高频范围几乎不随相对湿度变化.在10~105 Hz频率范围内,湿敏元件在11%~98%RH范围都出现了介电损耗的极大值,而且随着相对湿度增大,介电损耗极大值向高频方向移动.分析实验结果,在环境水分子浓度变化时,不仅电阻式湿敏元件感湿材料的电阻发生变化,介电常数也发生变化,水分子的极化也同时存在,但是其电阻随相对湿度的变化最为明显. 相似文献
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SnO2-LiZnVO4系湿敏陶瓷烧结工艺与电性能关系的复阻抗分析 总被引:1,自引:0,他引:1
采用共沉淀法制备出SnO2-LiZnVO4系湿敏试样,分别在不同烧结温度和保温时间下于空气中烧成,测量试样的湿敏特性,并通过复阻抗分析方法,研究了SnO2系湿敏元件烧结工艺与电性能的关系,探讨烧结工艺对敏感材料微结构的影响.结果表明: 适当调整烧结工艺参数可明显改善材料的微结构和湿敏性能,850℃×1h试样具有高湿电阻小灵敏度适中的湿敏特性;复阻抗分析表明,试样的电容在低频范围随烧结温度的升高和保温时间的延长先减小后增大,但高频范围几乎不随烧结温度的变化,且随时间的延长,试样的复阻抗谱的半圆弧弧长逐渐增大. 相似文献
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碱金属氧化物掺杂
对TiO2-V2O5系湿敏陶瓷的影响
’ 总被引:1,自引:1,他引:0
本文研究了碱金属氧化物掺杂对TiO2-V2O5系湿敏陶瓷的影响.结果表明:掺入碱金属氧化物和烧结温度等将影响材料的微结构及湿敏性能,其中含K2O材料有较高的湿敏性能.元件经聚合正硅酸酯溶液浸泡在50℃,85%RH下老化50h,提高了元件的湿度灵敏度和稳定性。 相似文献
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A composite material of nano-sized SiO2 and poly(2-acrylamido-2-methylpropane sulfonate) (poly(AMPS)) was used to make a humidity sensor. The infrared (IR) spectra and microstructure of the material were analyzed, and the humidity sensing and electrical properties of the sensor were measured. The sensor well responded to humidity with a relative good linearity, though it depended on the applied frequency. The temperature influence between 15 and 35 °C was −0.71 and −0.15% RH/°C at 30 and 90% RH, respectively. The sensor showed a negligible hysteresis and fast response time upon humidification and desiccation. The stability of the sensor in a highly humid and alcoholic environment increased with increasing the SiO2 content. The activation energy for conduction reduced with water adsorption. The different impedance plots observed at low and high relative humidity suggested different sensing mechanisms of the SiO2/poly(AMPS) composite material. 相似文献
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Highly sensitive humidity sensor at low humidity based on the quaternized polypyrrole composite film
Polypyrrole composite was fabricated by using chemical polymerization at room temperature, which was further quaternized with 1,4-bromobutane to prepare the humidity sensitive material. The electrical properties of the sensor were measured. The results showed that the quaternized polypyrrole composite film exhibited low impedance at very low humidity; the impedance value was about 780 kΩ at 11% RH and the impedance changed from 106 to 103 Ω between 11% and 95% RH, which was suitable for detection of low humidity. Moreover, the logarithm of impedance of the polypyrrole composite film varied linearly (R2 = 0.9916) with relative humidity in the range of 11–95% RH. Surface and cross-sectional morphology of the films, response–recovery time and hysteresis were also measured and estimated. The sensing mechanism of the sensor was also investigated. 相似文献
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《Sensors and actuators. B, Chemical》2006,113(1):142-149
Alkali salts of poly(2-acrylamido-2-methylpropane sulfonate) (PAMPS)-SiO2 and single-walled carbon nanotubes (SWCNTs)-SiO2-PAMPS were used as composite materials to make a humidity sensor. The impedances of these composite materials were measured at various humidities and temperatures in the frequency range of 1–100 kHz. The results indicated that the H+ form of the PAMPS-SiO2 composite film had the highest electrical conductance. For practical use, a humidity sensor, which was a low-resistance device, commonly required for electronic circuit compatibility, was prepared from SWCNTs-SiO2-PAMPS composites. The sensing mechanism of the SWCNTs-SiO2-PAMPS composite films were explained by considering the observed impedance plot and activation energy compared with a SiO2-PAMPS composite film. At low relative humidity (RH), new conductive paths were formed, whereas with increasing RH, the ionic contribution became prevalent. Other sensing properties of the SWCNTs-SiO2-PAMPS composite films such as effects of applied frequency, ambient temperature and hysteresis were also investigated. 相似文献
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Tong Yuan Rui Wangchang Lijie Ligang Xiaotian 《Sensors and actuators. B, Chemical》2008,131(2):687-691
Polypyrrole (PPY) materials were prepared by using chemical polymerization at room temperature for 96 h. A resistive-type humidity sensor was fabricated on a ceramic substrate with Ag–Pd interdigital electrodes. The humidity-sensing mechanism of the polypyrrole materials was discussed in terms of capacitance, direct current, complex impedance and dielectric loss properties. The discussion on the sensing mechanism indicated that not only electrons or ions but also dipoles contributed to the conduction in the whole relative humidity range. 相似文献