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现代科技、工业部门,对微量水分的测量、控制兴趣甚浓,且都有希望能灵敏、快速、连续等共同要求。测水方法甚多,如重量法、露点法、库仑法、压电晶体法等,各具特点,但都难以同时满足上述要求。以Al_2O_3湿敏元件为传感器的电容法能有效地解决这些问题,已在半导体电子工业、石油天然气、冶金、气象等等方面获得了广泛的应用。电容法的基本原则,是利用Al_2O_3湿敏元件中湿敏介质层吸(脱)水后介电常数的变化来测量物质(水分)组分。这种原则的应用可追溯到四十年代的各种介电常数检测器。1941年,Koller发表了Al_2O_3电容电抗湿度计,开创了Al_2O_3湿敏元件气相测湿的历史。Ansbarchers和Jason发现了阳极氧化铝对湿度变化的敏感性并对之进行了深入的研究。Cutting等又研制成功了“电容——电阻湿度计”,使Al_2O_3湿敏元件正式付诸测湿实用。Al_2O_3湿敏元件的大部分理论和实践
Modern science and technology, industrial sector, the measurement of moisture content, control interest is very strong, and there is hope can be sensitive, fast, continuous and other common requirements. Many methods of water measurement, such as gravimetric method, dew point method, Coulomb method, piezoelectric crystal method, have their own characteristics, but are difficult to meet the above requirements. The capacitance method using Al 2 O 3 as a sensor can effectively solve these problems and has been widely used in the semiconductor electronics industry, oil and gas, metallurgy, meteorology and so on. The basic principle of the capacitance method is to measure the material (moisture) component by using the change of the dielectric constant after absorbing (de-watering) water in the moisture-sensitive medium layer in the Al 2 O 3 humidity sensor. The application of this principle dates back to the various dielectric constant detectors of the 1940s. In 1941, Koller published an Al_2O_3 capacitive reactance hygrometer, which pioneered the history of gas phase wetting of Al_2O_3 moisture sensors. Ansbarchers and Jason discovered the sensitivity of anodized aluminum to humidity changes and conducted in-depth research. Cutting and other successful development of the “capacitance - resistance hygrometer,” Al 2 O 3 moisture sensor officially put into practical wet measurement. Most of the theory and practice of Al 2 O 3 moisture sensor