中文摘要：

以分析纯Bi（NO3）3·5H2O和Y（NO3）·6H2O为原料制备纳米β—Bi2O3和Bi2O3-Y2O3（75％（摩尔分数）Bi2O3＋25％（摩尔分数）Y2O3）粉体，平均粒度分别为40和30nm。经TG—DTA、高温XRD以及高温拉曼的研究结果表明，亚稳态的纳米β—Bi2O3粉体在升温过程中于420℃先向低温稳定的α-Bi2O3转变，在720℃时向δ-Bi2O3相转变，降温过程则是由δ→β→α。由于纳米Bi2O3具有很高的活性，使得相变温度比微米Bi2O#有所降低。纳米Bi2O3-Y2O3复合粉体升温过程中，Y2O3的固溶反应在较低温度（400℃）开始，500℃时β-Bi2O3完全转变为δ相，同时Y2O3完全固溶到δ-Bi2O3晶体中。Y2O3的掺杂使得Bi2O3的β→δ相转变温度大幅降低。

英文摘要：

With A. R. Bi（NO3）3 · 5H2O and Y（NO3）3 · 6H2O as raw materials, nano Bi2O3 and Bi2O3-Y2O3 （75mol % Bi2 O3 ＋ 25mol % Y2O3 ） powders were prepared and the average grain sizes were less than 4O and 3Onm, respectively. The study results of TG-DTA,high temperature XRD and high temperature Raman on phase transition behave of these powders showed that metastable state nanometer β-Bi2O3 transformed into stable α-Bi2 O3 at low temperature （420℃） first, then α-Bi2O3 transitioned into δ- Bi2O3 at 720℃ during the heated process; during the cooled process, phase transformation process was δ-β-α, because nano-Bi2O3 has higher activity which lead to lower transition temperature than micron-Bi2O3. The solid solution reaction of Y2O3 and β-Bi2O3 started at lower temperature （400℃） during the process of heated mixed nano Bi2O3-Y2O3 powder, b-Bi2O3 had almost completely transformed into δ-Bi2O3 at 500℃ and the solid solution reaction turned to end. The β→δ phase transformation temperature was lowered obviously by doping of Y2O3.