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以分析纯Bi(NO_3)_3·5H_2O和Y(NO_3)·6H_2O为原料制备纳米β-Bi_2O_3和Bi_2O_3-Y_2O_3(75% (摩尔分数)Bi_2O_3+25%(摩尔分数)Y_2O_3)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-Bi_2O_3粉体在升温过程中于420℃先向低温稳定的α-Bi_2O_3转变,在720℃时向δ-Bi_2O_3相转变,降温过程则是由δ→p→α。由于纳米Bi_2O_3具有很高的活性,使得相变温度比微米Bi_2O_3有所降低。蚋米Bi_2O_3-Y_2O_3复合粉体升温过程中。Y_2O_3的固溶反应在较低温度(400℃)开始,500℃时β-Bi_2O_3完全转变为δ相,同时Y_2O_3完全固溶到δ-Bi_2O_3晶体中。Y_2O_3的掺杂使得Bi_2O_3的β→δ相转变温度大幅降低。
The nanometer β-Bi_2O_3 and Bi_2O_3-Y_2O_3 (75% (molar fraction) Bi_2O_3 + 25% (mol fraction) Y_2O_3) powders were prepared by the analysis of pure Bi (NO_3) _3 · 5H_2O and Y (NO_3) Respectively 40 and 30 nm. The TG-DTA, high temperature XRD and high temperature Raman results show. The metastable nanometer β-Bi_2O_3 powder changes to α-Bi_2O_3 with low temperature stability at 420 ℃ and δ-p_α to α-Bi_2O_3 phase at 720 ℃. Due to the high activity of nanometer Bi_2O_3, the phase transformation temperature is lower than that of Bi_2O_3.蚋 rice Bi_2O_3-Y_2O_3 composite powder during warming. The solid solution reaction of Y_2O_3 began at lower temperature (400 ℃), and completely changed to δ phase at 500 ℃. At the same time, Y_2O_3 completely dissolved into δ-Bi_2O_3 crystal. The doping of Y 2 O 3 makes the β → δ phase transition temperature of Bi 2 O 3 greatly reduced.