电化学法制备阳极多孔氧化铝及其在湿敏传感器中的应用

发布时间：2018-06-07 13:43

本文选题：纳米材料 + 多孔阳极氧化铝　；参考：《上海交通大学》2011年硕士论文

【摘要】：电化学氧化高纯铝片制得的多孔氧化铝模板具有独特的规则有序的纳米孔阵列,在纳米技术、物理光电子学等方面具有广泛的应用。该材料的制备方法简单低廉,近几年来越来越多的引起了人们的关注及深入研究。本文首先介绍了纳米材料的发展历史,制备工艺和研究手段。接下来介绍了传感器分类,湿敏传感器原理和分类,并详述湿敏传感器的主要性能指标。本文主要研究高场条件下,电化学方法制备高度有序纳米多孔氧化铝模板的制备工艺及在湿敏传感器中的应用。在传统条件下,多孔阳极氧化铝的大多在低场条件下制备,由于反应速率较慢,限制了其进一步应用。高场条件下反应较快,但制备工艺很不完善,为此,我们研究了多孔氧化铝在高场下制备工艺。在研究过程中,我们得到了高场条件下完整的电流时间曲线。通过显微研究,我们发现高场条件下氧化铝的生长过程和低场有很多区别:在电流特性曲线上,高场的电流上升阶段是孔增长阶段,而低场则是孔引发阶段。孔间距是随时间变化的过程,在一次氧化中,表面的孔距是氧化10min后的一半。这一方面,我们运用电流变化导致的应力变化来解释。同时这种应力变化也会造成表面的塑性破坏等特点。由于多孔氧化铝高度有序的孔阵列结构,其孔隙率非常高,同时氧化铝对于湿度有很好的响应性,所以多孔阳极氧化铝也常被用来制备湿敏传感器。高场电化学氧化得到的氧化铝薄膜中含有高含量的杂质离子,而杂质离子有助于电子导电,这会使得在低湿度区域湿敏传感器有较好的灵敏度。在文中,我们通过扩孔改变表面的杂质分布来改善低湿度的灵敏度,并且适当降低高湿度灵敏度。由于在草酸中进行氧化,氧化铝薄膜内含有草酸根阴离子,我们进行扩孔工艺,使得草酸根分解产生二氧化碳。由于二氧化碳的解离度很高,在水溶液中极易解离成项质子。根据高湿度质子导电的机理,很容易提高湿敏传感器的灵敏度。由于低湿度灵敏度提高,高湿度区域灵敏度降低,传感器的线性响应提高。以上研究得到了国家自然科学基金(10874115),国家重点基础研究项目(2010CB933702)及上海市纳米科技专项(0952nm01900),上海市重大基础研究目(08JC1411000)和中国高等教育博士点研究基金的资助,特此感谢!
[Abstract]:Porous alumina templates prepared by electrochemical oxidation of high purity aluminum wafers have unique regular ordered nano-porous arrays and have been widely used in nanotechnology physical optoelectronics and so on. The preparation method of this material is simple and cheap, and more people pay attention to it in recent years. In this paper, the development history, preparation technology and research methods of nanomaterials are introduced. Then, the sensor classification, the principle and classification of humidity sensor are introduced, and the main performance indexes of humidity sensor are described in detail. The preparation process of highly ordered porous alumina template and its application in humidity sensor were studied in this paper. Under the traditional conditions, porous anodic alumina is mostly prepared in low field, which limits its further application due to its slow reaction rate. Under the condition of high field, the reaction is fast, but the preparation process is not perfect. Therefore, we have studied the preparation process of porous alumina under high field. In the course of the study, we obtained the complete current time curve under the condition of high field. Through microscopic study, we find that there are many differences between the growth process of alumina and the low field in the high field. In the current characteristic curve, the current rising stage in the high field is the pore growth stage, while the low field is the orifice initiation stage. The pore spacing varies with time. In the first oxidation, the pore spacing of the surface is half of that after 10min oxidation. In this respect, we use changes in stress caused by changes in current to explain. At the same time, the change of stress will also cause plastic failure on the surface. Porous anodic alumina is often used to fabricate humidity sensors because of its highly ordered pore array structure and its high porosity and good humidity response. The aluminum oxide film obtained by high field electrochemical oxidation contains high content of impurity ions, which is helpful to electron conduction, which makes the humidity sensor have better sensitivity in low humidity region. In this paper, we improve the sensitivity of low humidity and reduce the sensitivity of high humidity by changing the surface impurity distribution. Because oxalate is oxidized in oxalic acid, oxalate anion is found in alumina film. Due to the high degree of dissociation of carbon dioxide, protons are easily dissociated in aqueous solution. According to the mechanism of high humidity proton conduction, it is easy to improve the sensitivity of humidity sensor. Because of the increase of low humidity sensitivity, the sensitivity of high humidity region is decreased, and the linear response of sensor is improved. The above research is supported by the National Natural Science Foundation of China 10874115, the National key basic Research Project 2010 CB933702), the Shanghai Nano-Science and Technology Project (0952nm01900), the important basic Research item of Shanghai (08JC1411000) and the doctoral Research Foundation of higher Education of China. Thank you for this!
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TB383.1;TP212.1

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