| Porous alumina films have attracted great attention due to their interesting porous structure and potential applications in many fields. Porous alumina film used widely was maily prepared by conventional anodization. The pore size ranged from 5 to 100 nm, pore density ranged 109-1011 pore/cm2 and pore channel was perpendicular to the aluminum substrate. Applications of these porous structure materials included electronic, optical, preparation of nanomaterials, sensors and microreactors. But the pore scale was small and the range was narrow. So fabrication of well-aligned macro porous alumina film with pore diameter between nanometer and micrometer size could widen its application in many fields, which is of importance to both basic research and applied research. In this dissertation, the relationship between the morphology of porous high voltage anodization film (HVAF) and the electrolyte's compositions and their concentrations was investigated by high voltage anodization. Some applications of the porous HVAF were also studied. 1. For the first time, aluminum high voltage anodization was researched in mixed acid electrolytes containing three or four substances and Porous HVAF with pore size ranged from 100 to 500 nm could be obtained. According to the scanning electron microscopy (SEM) of the cross-section of HVAF, this kind of macro porous HVAF contained two layers: barrier layer and porous layer. The thichness of barrier layer was about 500 nm and related to the anodic voltage. The thickness of porous layer was about tens of micro-meters. The pore channel was parallel to each other and perpendicular to the barrier layer and the aluminum substrate. Through adjusting the compositions and their concentrations of the electrolyte, both pore size and pore architecture of porous HVAF could be changed. This kind of porous HVAF with pore size between nanometer and micrometer could see a brilliant future in materials preparation and their functional applications. 2. By adding Polytetrafluoroethylene (PTFE) emulsion in mixed acid electrolyte, the PTFE/Al2O3 composite film could be fabricated on aluminum substrate. The SEM and X-Ray energy dispersive spectrum (EDS) results showed that PTFE nanoparticles were filled into pores of HVAF. When the concentration of PTFE emulsion increased to 1.5 ml/L, the pore could be filled with PTFE nanoparticles completely. 3. In TiO2 sol, nano TiO2 were prepared by immersing, DC electrolyzing, AC electrolyzing methods. The morphologies of nano TiO2 prepared by above three methods were nano-particle, short nano pillar and nano wire. The nano wires prepared by AC electrolyzing were formed directionally on the walls of HVAF pores and the length was about 1000 nm. The specific surface area of nano wires was much larger than that of nano particles and short nano pillars, wich resulted in its better UV catalyses for 0.2 mM sodium dodecyl benzene sulfonate (SDBS) solution. 4. The formation process of well-aligned porous HVAF in mixed acid electrolyte was researched by anodic polarizaion curves, SEM and XRD methods. The results showed that the process could be divided into three steps: (a) with the increasing of anodic current density, barrier layer and porous layer were formed quickly. The pore size was about 100 nm. (b) under high voltage and big current, the porous layer could grow with high speed. The pore size increased with the increasing of anodizing time. (c) when anodic current density decreased to a small value, the formation of HVAF ceased, but the dissolving of porous layer was still on going. The process of the fabrication of well-aligned regular polygon pores with big pore size was finished ultimately.
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