阳极氧化铝纳米孔洞形成过程研究

【作者】 俞华栋；

【导师】 朱绪飞；

【作者基本信息】 南京理工大学 ， 高分子化学与物理， 2008， 硕士

【摘要】 传统理论认为“酸性场致溶解”是多孔阳极氧化铝(简称PAA)孔洞产生和孔道发展的主要原因,但是“酸性场致溶解”理论对PAA的六棱柱元胞和半球形底部结构无法给出合理解释。为进一步探讨PAA的形成机理,本文研究了不同电解液中铝的阳极氧化过程,利用电化学阳极氧化曲线测试系统和扫描电子显微镜等仪器,对铝的阳极氧化V-t曲线和氧化膜表面形貌进行了表征。结果表明:“酸性”这个因素并不是产生多孔的必要条件,在酸性较弱的磷酸二氢铵电解液中也能得到类似孔道。在致密型电解液中(癸二酸铵的乙二醇溶液)也能形成多孔,且随着磷酸加入量的增大孔道密度增加。氧气析出是由于碰撞电离系数α和初始雪崩电子电流j0的增加引起的。在此基础上提出了新的PAA生长模型:认为孔道的形成是“氧气泡模具效应”的结果,并且对阳极氧化的V-t曲线进行了新的解释。本文提出的“氧气泡模具效应”对PAA梅花状结构的自组织过程和锯齿型孔道进行了诠释。其中锯齿型孔道的PAA结构可以作为纳米材料的新型模板。更多还原

【Abstract】 Traditional theory claims that the main mechanism for the formation of porous anodic alumina （PAA） is acidic electricfield-assisted dissolution, but it cannot give a reasonable explanation for the structure of hexagonal cells and hemispherical pore base in PAA. In order to study the growth mechanism of PAA, we chose several electrolytes to perform aluminum anodization. The anodization process and PAA films were characterized by means of Voltage-time curves. The result indicates that acidity of electrolyte is not the necessary condition. We also find the regular porous in NH4H2PO4 electrolyte.PAA can also be observed in barrier film-forming electrolyte （ammonium sebacate solution in ethylene glycol） and the pore channels will be much denser with the H₃PO₄ increasing. Augment of constantαand j₀ induces O₂ separating out. Besides we present a new growth model and formation mechanism of PAA, i.e. oxygen bubble mould effect results in regular channels of PAA films. We also give a new explanation for the V-t curve of anodization.Oxygen bubble mould effect can explain the formation mechanism of the plum blossom patterns on PAA and serrated nanopore. The serrated nanopore arrays in PAA could also be used in a wide range of future nanostructure fabrications.更多还原