Fabrication, Characterization And Application Of Porous Alumina Film

In recent years , alumina membranes have attracted increasing amount of attention due to their potential use in several field of technological interest , such as micro and ultrafiltration catalytic reactors and electrolytes for proton exchange, wear-resistance coatings. PAA membranes with straight nanochannels of uniform diameter and length have been widely used to fabricate one-dimensional nanomaterials with controllable orientation, position and size, or two dimensional nanoparticle arrays. 1. Effect of glycerin on the process of anodization. In this experiment, AAO with parallel nanochannels was anodized by anodizing high-purity Al in 3% oxalic acid solution and 3% oxalic acid solution with additive 10g/L. The process of alumina membranes growth were recorded by electrochemical computer test system . The morphology of the samples was examined by scanning electron microscope (SEM) and structure was tested by XRD, composition of the alumina and anodization electrolyte was found by IR transparent spectra method. The density-voltage show that glycerin can decrease the speed of the growth of barrier layer and nanopores, The XRD sprctra show that only amorphous alumina exists in the membranes prepared either in oxalic acid solution or oxalic acid solution with organic additive. According to the measurement , we come to the conclusion that the glycerin doesn't change the structure of alumina. IR spectra show that the additive had reacted during the anodization process and effect the diameter of the nanopore. 2. Mechanical property of alumina membranes. Mchanical property of AAO was measured by crook break measurement. The result show that first the property of membranes obtained on annealed aluminium is better than cold aluminium. Second, the property of the samples obtained in oxalic acid solution with glycerin is better than that obtained in oxalic acid solution. 3. Fabrication of thermoelectric materials in AAO. In this experiment, AAO was used as a template to electrodepose Bi2Te3 nanowires. The effect of voltage , diameter of nanopore and length of nanopore on the process of deposition were studied by electrochemical working system. Morphology and composition of nanowire were tested by TEM. Thermoelectric properties of the material were measured by thermoelectric test system developed by our team.