Process Of Barium Titanate Nanotubes Prepared By Anodic Oxidation

This paper mainly explored the preparation process of BaTiO₃nanotube arraysby anodic oxidation and hydrothermal synthesis. Firstly, amorphous TiO₂nanotubeswas prepared by anodic oxidation method in NH4F electrolyte. And then amorphousTiO₂nanotubes were turned to be crystalline TiO₂nanotubes by rapid thermalprocess. Finally BaTiO₃nanotubes were prepared by hydrothermal synthesis methodin Ba（OH）₂solution with crystalline TiO₂nanotubes as the template.When anodizing in NH4F electrolyte, voltage, electrolyte concentration andoxidation time were respectively explored the influence to the formation of TiO₂nanotubes. The best preparation process of anodic oxidation was obtained with theanalysis of their morphology and structure through SEM and XRD. The voltageshould be set from10V to20V, and15V is better. Electrolyte concentration shouldbe set from10g/L to40g/L. Oxidation time should be set as about30min. Theprepared TiO₂nanotubes is amorphous. The nanotube diameter is from90nm to110nm, the inner diameter is from30nm to40nm, and the length of the tube is about1μm.Amorphous TiO₂nanotubes could be turned to be crystalline TiO₂nanotubes byrapid thermal process. When the rapid heat treatment temperature is400or500℃,the amorphous TiO₂nanotubes are turned to be Anatase nanotubes. When the rapidheat treatment temperature is600or700℃, the amorphous TiO₂nanotubes areturned to be Rutile nanotubes.When hydrothermal synthesis reaction was dealed in Ba（OH）₂solution withAnatase nanotubes as the templae obtained by rapid thermal annealing at500℃.Hydrothermal time, the concentration of Ba（OH）₂solution, hydrothermaltemperature and rapid thermal processing temperature were explored the influenceto the formation of BaTiO₃nanotubes. The best preparation process of hydrothermalsynthesis was obtained with the analysis of their morphology and structure throughSEM and XRD, and the test of ferroelectric properties. The concentration ofBa（OH）₂solution should be0.1M, the hydrothermal temperature shoule be200℃,hydrothermal time should be3h. At the point the nanoparticles size of the preparedBaTiO₃above BaTiO₃nanotubes is about100-400nm. The dispersibility anduniformity of the nanoparticles are great, and crystallinity of BaTiO₃is relativelyhigh. BaTiO₃nanotubes have excellent ferroelectric properties. Residualpolarization and coercive field are increasing with the increasing of the applied electric field. The largest residual polarization is about0.5509μC/cm2, and thelargest coercive field is approximately19.242kV/cm.