PROPERTIES OF MODIFIED ANODIC-SPARK-DEPOSITED ALUMINA POROUS CERAMIC FILMS AS HUMIDITY SENSORS

被引:15
作者
CHEN, Z
JIN, MC
ZHEN, C
CHEN, GH
机构
[1] Center for Materials Analysis, Department of Materials Science and Engineering, University of Electronic Science and Technology of China, Chengdu
关键词
HUMIDITY; ALUMINA; FILMS; ANODES; ELECTRICAL PROPERTIES;
D O I
10.1111/j.1151-2916.1991.tb04106.x
中图分类号
TQ174 [陶瓷工业]; TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
alpha-Alumina films formed by anodic spark deposition in the melt of NaHSO4-KHSO4 mixture (200-degrees-C) exhibited a porous structure. It has been found that the porosity and amount of alpha phase varied with anodic current density. By electrical measurements, films were found to exhibit a continuous open-pore structure, causing failure of humidity sensors. This problem can be overcome by reanodization of the anodic-spark-deposited alumina films in either borax aqueous solution or sulfuric acid solution for a short time to form an effective barrier layer at the pore base. The modified anodic-spark-deposited alumina films showed highly sensitive response to water vapor change in the range of -76-degrees to +20-degrees-C dew point with much improved long-term stability. The humidity characteristics of the alpha-alumina films were qualitatively explained in terms of the BET theory and condensation theory.
引用
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页码:1325 / 1330
页数:6
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