材料学论文 多孔阳极氧化钛纳米管的制备与形成机理的研究.doc

摘要 按照酸性场致溶解理论（Porous Anodic Titania Nanotubes, PATNT）只能在含氟离子电解液生成而在不含氟离子电解液中只能生成（Barrier Anodic Titania, BAT）孔道的产生和加深是酸性场致溶解但是酸性场致溶解理论解释六方晶胞纳米孔道的形成原因。 本文首先探讨了PATNT传统形成机理的局限性，指出PATNT孔道的形成原因不是酸性场致溶解，而是氧气的析出。在前人研究基础上提出PATNT新的生长模型和形成机（Oxygen Bubble Mould Effect），对纳米孔道的产生及发展过程、六方晶胞以及纳米孔道的半球形底部等问题作出了合理的解释，并通过在电解液中添加还原剂减少氧气、减小压力增加氧气两种手段验证了确性。第二，为了探讨最佳的预处理方式，研究了三种不同的预处理方式对金属钛及PATNT表面形貌的影响，并对不同表面形貌成因作出解释。第三，通过改变阳极氧化电压、时间以及电解液温度三种工艺条件进行钛阳极氧化，将制备的样品使用场致发射扫描电镜、电化学测试、系统元素成分分析进行表征，通过对SEM图像、阳极氧化电流-时间曲线以及ED能谱的分析，确定阳极氧化法制备PATNT最佳的工艺条件。最后，为了制备表面形貌光滑平整、纳米管阵列高度有序的PATNT，本文研究了酸处理、超声处理两种后处理方式对PATNT表面形貌和结构的影响，探索了效果最好的后处理方式。 关键词：多孔阳极，壁垒型，阳极氧化，形成机理，氧气气泡模具效应 Abstract According to the theory of acidic field-assisted dissolution, Porous Anodic Titania Nanotube (PATNT) can only be prepared in containing fluorine ions electrolyte, while Barrier Anodic Titania(BAT) forms in fluorine ions free electrolyte, generation and deepening of PATNT channels are caused by acidic field-assisted dissolution. But the theory cannot give a convincing explanation for hexagonal close packed structure and hemispherical bottom structure of channels. At first, the limitations of traditional PATNT formation mechanism are discussed. We point out that the formation of PATNT channels does not result from acidic field-assisted dissolution but evolution of oxygen in nanotubes. And then we present a novel growth model and new formation mechanism based on previous studies of PATNT. The oxygen bubble mould effect can explain some problems reasonably, such as the generation and development process of nanochannels, hexagonal close packed structure and hemispherical bottom structure. Then two methods are used to prove the novel model indirectly. Secondly, in order to seek for the best pretreatment method, we study three different pretreatment processes which have different influence on the surface morphology structure of titanium and PATNT. Many kinds of the surface morphologies of titanium and PATNT can be seeen and th