Molten salt synthesis of La₂Zr₂O₇ ultrafine powders

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• 作者：Zhong Huang^a ; Faliang Li^a ; Chengpeng Jiao^a ; Jianghao Liu^a ; Juntong Huang^b ; Lilin Lu^a ; Haijun Zhang^a ; ^{zhanghaijun@wust.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Shaowei Zhang^a ; ^b ; ^{zhangshaowei@wust.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：La2Zr2O7 ; Molten salt ; Ultrafine powders
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：42
• 期：5
• 页码：6221-6227
• 全文大小：2146 K

文摘

Ultrafine powders of pyrochlore-type La₂Zr₂O₇ were synthesized via a simple molten salt mediated process using zirconium oxide and lanthanum oxide as raw materials, and sodium chloride, potassium chloride and sodium fluoride to form a reaction medium. The effects of reaction temperature, salt/reactant ratio and salt type on the La₂Zr₂O₇ formation were investigated. Among the three attempted salt assemblies (KCl–LiCl, Na₂CO₃–K₂CO₃, and NaCl–KCl–NaF), NaCl–KCl–NaF showed the best accelerating effect on the La₂Zr₂O₇ formation. At a given temperature, the La₂Zr₂O₇ content in the final products increased with the increase in the salt amount. Phase pure submicron sized La₂Zr₂O₇ ultrafine powders were obtained after 3 h firing at 1100 °C with the salt/reactant weight ratio of 5:1 or at 1200 °C with salt/reactant weight ratio of 3:1. The synthesis temperature (1100 °C) was much lower than that required by the conventional solid-state mixing method or a wet chemical method. The “dissolution–precipitation” mechanism had dominated the synthesis process.