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Study on Preparation and Growth Mechanism of One-dimentional Bi2O3 Powders Through Hydrometallurgy

Author: LiuLi
Tutor: JinShengMing
School: Central South University
Course: Materials Science
Keywords: α-Bi2O3 β-Bi2O3 whiskers nanowires crystal growth
CLC: TB383.3
Type: Master's thesis
Year: 2011
Downloads: 93
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Abstract


Bi2O3 hasα、β、δphases and different kinds of crystal structures. The fields in which Bi2O3 is usually used include ceramic powder materials, photoelectric materials,electrolyte materials, high-temperture superconductor materials, activators and so on. In contrast to importance, However, However, littleattention were paid to the preparation of one dimensional (ID) Bi2O3 powders,, and only few of literatures about 1D Bi2O3 structures have been reported so far. This dissertion aims to study on the preparation and characterization of 1D Bi2O3 powders through hydrometallurgy.A chemical precipitation method has been developed to prepare a-Bi2O3 whisker using Na2SO4 as additive in alkaline medium. The effects of concentration of precipitator, surfactants and reaction time on the formation of a-Bi2O3 have been investigated in detail using XRD, SEM and TEM. a-Bi2O3 whiskers with averge diameter of 0.8μm and aspect ratio of 50 have been suceessfully synthesized through changing the synthenic conditions. The possible growth mechanism of the a-Bi2O3 whiskers were also proposed according to the specific morphological transition formed in the experiment, and crystal growth formed through growth units’interface overlapping and ultimate formation into whisker anisotropically.Beta-Bi2O3 (β-Bi2O3) nanowires have been synthesized via a facile hydrothermal approach using commercial bulks Bi2O3 and K2SO4 as raw materials. The samples were characterized by means of XRD, SEM, IR and TEM. The influences of pH, molar ratio of Bi2O3 to K2SO4, K2SO4 concentration, the reaction temperature and reaction time on the final morphologies of beta-bismuth oxide were investigated. The cooperative mechanism between the SO42- oriented attachment and template effect of K+is responsible for the morphology ofβ-Bi2O3. The template model was established to explain the formation of the effect of reaction factors on the morphology ofβ-Bi2O3.

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