Preparation And Study Of Porous Anodic Aluminum Templates

Anodic aluminum oxide template (AAO) has been nearly a hundredyears of history. Because of the advantages such as simplepreparation technology, cheap raw materials, highly ordered porearray and pore size adjustable in a certain range, AAO has won a widerange of applications.To obtain AAO template with different structural parameters, weprepared a series of AAO templates using the two-step anodizationprocess in this paper. The composition and structure of the templateswere analyzed by x-ray diffraction (XRD) and we observat themorphology of AAO using scanning electron microscopy (SEM). wesummarize the conclusions which presente in this paper as follows:(1) A series of highly ordered AAO templates were obtained insulfuric acid, oxalic acid, phosphoric acid and citric acid, respectively.The impact of electrolyte type, electrolyte temperature, oxidationtime, oxidation voltage and expanding time on the morphology of thetemplates were studied. The result shows that in different electrolytethe oxidation voltage is different, also the pore diameter of the template increase with the adding of oxidation voltage. For example,in oxalic acid electrolyte the oxidation voltage generally falls in30v-80v, in which40v is the best voltage, and the corresponding porediameter is about60nm. While in citric acid the oxidation voltagebetween260v to300v can form the regular AAO templates, and thebiggest pore diameter up to600nm. Prolonging the secondaryoxidation time can add the thickness of the Anodic aluminum oxidetemplate, the ratio of length and diameter will increasecorrespondingly. By a series of experimental study, we obtained someexperimental parameters of AAO templates with different pore sizeand different length which provide a broader space for it.(2) A series of AAO templates were prepared in oxalic acid-citricacid mixed solution, and the influence of direct voltage method andgradually rising voltage mode on the preparation of the AAO templatewas studied. It is found that gradually rising voltage mode is moresuitable for the preparation of AAO templates under high voltage;different ratio of mixture in the preparation of AAO templates useddifferent oxidation voltage. In1:60oxalic acid and citric acid mixedsolution (Ro:c=1:60), oxidation voltage change from190v to220v canform highly ordered Anodic aluminum oxide template, and the porediameter is about420nm. In Ro:c=1:10solution the optimal oxidationvoltage is140v, and diameter up to290nm. With the increase of citric acid concentration in mixed acid solution, the oxidation voltagepreparing high ordered AAO templates increases, and the porediameter increases under corresponding oxidation voltage. AsRo:c=1:30solution for example, we studied the influence of electrolytetemperature on AAO templates. It found that with the electrolytetemperature increases, the pore growth rate speed up, but the impacton the surface of template is little.