Synthesis And Structural Characterization Of AAO Templates And One-dimensional Nanomaterials Of Neodymium Compounds

Anodic aluminium oxide membrane(AAO)which is fabricated by anodic oxide of A1 not only has a simple process but also contains uniform parallel pores and high pore density. Furthermore, the pore diameter is controllable according to practical needs. These characteristics allow the use of AAO as template. In this paper, the anodic aluminium oxide templates with regular nano channels were prepared through a two-step preparation technology successfully and the influence of many factors on the AAO templates was investigated in detail. Then one-dimensional nanomaterials of neodymium compounds were prepared with the AAO templates.(1) The Anodic aluminum oxide templates were prepared by anodizing highly pure aluminum foils through a two-step preparation technology. The oxidation was carried out in oxalic acid solution with the graphite electrode as a cathodal electrode, the aluminum foil as an anodic electrode. The effects of the electrolyte concentration, oxidation time, oxidation voltage on the morphologies of the AAO and the influence of the roughness of the aluminum foil on the orientation of the nano channel were investigated. The results indicated that the pore size became smaller and the pore array became more uniform in the high electrolyte concentration and oxidation voltage. Electrolyte oxidation time had few effect on the pore size, but affected tunnel array, if the oxidation was carried out longer, the order of the array was better. The orientation of the tube growth was strongly affected by the substrate surface with roughness in micro scale (5³0um). For Al substrate with surface roughness in nano scale, the tube growth was scarcely affected by the surface roughness.(2) The preparation of Nd2O3 nanowires were performed through sol-gel process assisted with porous anodic aluminum oxide (AAO) as a template from aqueous Nd(NO3)3 and urea. In order to investigate the influence of different infiltrations on the syntheses of Nd2O3 nanowires in the AAO membrane, pressure infiltration instrument and conventional infiltration instrument were used. The morphology and the phase composition of the prepared nanowires were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy disperse spectroscopy (EDS). The results showed that the Nd2O3 nanowires could be successfully synthesized by using the two infiltration instruments. However, a good filling could be obtained using the pressure infiltration instrument and the synthesized Nd2O3 nanowires grew in the AAO template had a high aspect ratio.(3) Nd(OH)₃ nanowires were prepared using direct current potentiostatic deposition in porous anodic aluminum oxide template at room temperature. The morphology and the phase composition of the prepared nanowires were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The SEM showed that the nanowires had successfully grown into the nano channels of the AAO template. These nanowires had uniform diameters of about 40 nm, which corresponded to the pore size of the template used.