【作者】 胡艳丽；

【导师】 雷惊雷；

【作者基本信息】 重庆大学 ， 物理化学， 2008， 硕士

【摘要】 目前对阳极氧化铝模板的形成机理的研究,研究者主要对其形成过程的机理模型研究的较多,而对其形成过程的动力学的研究尚不多见。论文在能形成多孔阳极氧化铝模板的条件下,对铝模板形成动力学进行了以下研究:①分析不同温度下阳极氧化铝模板形成过程中的电流密度-时间的变化曲线,该曲线经历了下降、上升、平稳三个阶段。由此可以推断,在相应条件下,均能够生成多孔阳极氧化铝膜。②分析铝阳极氧化过程中阴极和阳极所发生的电化学反应,并采用铝试剂分光光度法,测量1.0mol/L的硫酸电解液中不同时刻对应铝离子的浓度,然后根据化学动力学理论,确定出所在实验条件下铝失电子反应为零级反应;控制温度为变量,可以得出不同温度下的速率常数;根据阿仑尼乌斯公式,确定出阳极铝失电子反应的表观活化能Ea=53.8 kJ·mol-1。实验过程中低温有利于阳极氧化铝模板的形成,与理论相符。③根据对Tafel极化曲线的分析,求出铝阳极氧化过程中电极动力学基本参数,并推测了该过程的反应历程。同时,针对阳极氧化铝模板的制备过程中铝片预处理过程繁琐的缺点,论文探讨了预处理工艺的简化。通过改变铝的预处理工艺中的退火、除油、除氧化层、化学出光四个工序,考察每个预处理工序对所得模板形貌的影响。实验中电解液为0.13mol/L的草酸溶液,通过两步直流恒压阳极氧化法制备氧化铝模板,并采用原子力显微镜对其表面形貌进行了观察,结合阳极氧化初期电流-时间的变化,考察了预处理工艺中每个步骤对阳极氧化铝模板形貌的影响。得到如下结论:①经过对制备样品的AFM表征,表明可以通过两步阳极氧化法成功制得阳极氧化铝模板,所制备的阳极氧化铝模板是由六面柱体状的膜胞所构成,微孔孔径大小基本相同,平均约为200nm;孔分布均匀有序,孔密度为109/cm~2。②探讨预处理各个工序对模板有序规则性的影响,并在简化的条件下得到了规则有序的阳极氧化铝模板。对比实验表明,在经除油、不经高温退火、不经化学出光以及不用除去自然氧化层的预处理条件下,通过两步阳极氧化法仍能得到高度有序的多孔阳极氧化铝模板,使制备工艺得到了简化。更多还原

【Abstract】 It was rearched on some mechanism models at present for the formation mechanism of the anodic alumina templet. However, investigators didn’t attach importance to the dynamics mechanism from the electrolyte and electrode aspect. Therefore, it is necessary to research the dynamics mechanism of anodic alumina templet deeply. This paper has done the following work under the sistuation that can form porous alumina templet with nano-pore array structure:①The curves of current density– time are analyzed during the formation of anodic alumina template at different temperatures, the curves have experienced three stages of declining, rising and going steady. It can be inferred that porous anodic alumina film are able to generate in the appropriate conditions, and the speed of electrochemical reaction also increases with the increase of temperature.②Reactions which take place on cathode and anode are analyzed, and the concentration of aluminum ion is mensurated by aluminum reagent spectrophotometry insulfuric acid electrolyte of 1.0 mol / L. Then, basing the chemistry dynamics theories, the reaction that aluminum loses electronics is confirmed zero order reaction, and the velocity constants are ascertained at different temperature by makeing temperature for variable, so the apparent activation energy can be confirmed basing Arrhenius equation, and the apparent activation energy is 53.80 kJ·mol-1. Theoretically, the low temperature is advantageous to the reaction which has low apparent activation energy, and the the experiment’s requests are even the same as the theory’s.③Basing the analysis of Tafel curves, the electrode dynamics parameters and the reaction course are ascertained,When scholars research the preparation of anodic alumina templet, applications, and the formation mechanism, it is required to go through some miscellaneous pretreatment procedures. To simplify the pretreatment process for prepaing anodic alumina templet, the influence of annealing, degreasing, chemical polishing on the morphology of anodic alumina templet are investigated in this thesis. During the experimental process, anodic alumina templets are prepared under constant potential by DC in oxalic acid solutions of 0.13mol/L through a two-step anodic oxidation. The morphology of anodic alumina templet is observed by atomic force microscope, and the influences of each step of pretreatment process on the characteristics of anodic alumina templet are discussed by analyzing the current change in the initial process of anodic oxidation. The following conclusions are gotten in this parer:①It can be indicated that anodic alumina templets are successfully prepared by observig with atomic force microscope, the anodic alumina templet is compose of a many six-cylinder-shaped cells, the average diameter of pores is basically the same size with each other about 200 nm, the hole density is 109 / cm2, and the holes distribute evenly in an orderly manner.②The influence of each pretreatment procedure on the morphology of anodic alumina templet is investigated, and regular anodic alumina templet is successfully prepared under the conditions of the simplification. A series of comparative experiments show that after degreasing, well-arranged porous alumina films are obtained without annealing, chemical polishing and removing natural oxide layer, and it makes the preparation of porous alumina films simplified.更多还原