The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffr...The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi（NO3）3 reacts at 90℃ for 2h, the Bi2O3 powders with 60nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi 3+ to O 2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.展开更多
The study of tetragonal ZrO<sub>2</sub>（Y<sub>2</sub>O<sub>3</sub> 3% mol） has attracted considerable attention becauseof its various important applications. In the past several y...The study of tetragonal ZrO<sub>2</sub>（Y<sub>2</sub>O<sub>3</sub> 3% mol） has attracted considerable attention becauseof its various important applications. In the past several years, a lot of scientists haveput their efforts on synthesizing highly pure, agglomerate-free and nanometer-sized （i.e. par-ticle size less than 100nm）ZrO<sub>2</sub>（Y<sub>2</sub>O<sub>3</sub> 3% mol） powder （hereinafter as nano powder forshort）.展开更多
文摘The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi（NO3）3 reacts at 90℃ for 2h, the Bi2O3 powders with 60nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi 3+ to O 2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.
文摘The study of tetragonal ZrO<sub>2</sub>（Y<sub>2</sub>O<sub>3</sub> 3% mol） has attracted considerable attention becauseof its various important applications. In the past several years, a lot of scientists haveput their efforts on synthesizing highly pure, agglomerate-free and nanometer-sized （i.e. par-ticle size less than 100nm）ZrO<sub>2</sub>（Y<sub>2</sub>O<sub>3</sub> 3% mol） powder （hereinafter as nano powder forshort）.
