Preparation of ¦Á-Bi₂O₃ from bismuth powders through low-temperature oxidation

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• 作者：Ji-yong XIA ; Mo-tang TANG ; Cui CHEN ; Sheng-ming JIN ; Yong-ming CHEN
• 关键词：bismuth powder ; low-temperature oxidation ; ¦Á-Bi2O3 ; oxidation kinetics
• 刊名：Transactions of Nonferrous Metals Society of China
• 出版年：2012
• 出版时间：September, 2012
• 年：2012
• 卷：22
• 期：9
• 页码：2289-2294
• 全文大小：1624 K

文摘

¦Á-Bi₂O₃ powders were prepared from nanometer Bi powders through low-temperature oxidation at less than 873.15 K. XRD, SEM, TEM and HRTEM were used to characterize the structure and morphology of Bi powders and Bi₂O₃ particles. Kinetic studies on the bismuth oxidation at low-temperatures were carried out by TGA method. The results show that bismuth beads should be reunited and oxidized to become irregular Bi₂O₃ powders. The bismuth oxidation follows shrinking core model, and its controlling mechanism varies at different reaction time. Within 0-10 min, the kinetics is controlled by chemical reaction, after that it is controlled by O₂ diffusion in the solid ¦Á-Bi₂O₃ layer. The apparent activation energy is determined as 55.19 kJ/mol in liquid-phase oxidation.