朱红艳
,
马伟民
,
闻雷
,
管仁国
,
马雷
,
吴南
金属学报
doi:10.3724/SP.J.1037.2011.00735
采用反向滴定共沉淀法制备出(Y, Gd)2O3∶Eu3+前躯体, 再在不同温度下煅烧, 获得(Y, Gd)2O3∶Eu3+纳米粒子, 用XRD和SEM对样品物相组成及形貌进行了表征; 用TG--DTA获得了样品在不同升温速率下的热分解曲线. 结果表明, 前躯体在煅烧过程中的物相变化分为3个阶段, 用Doyle-Ozawa法和Kissinger法分别计算出各个反应阶段的表观活化能, 其平均值分别为191.54, 557.05和236.58 kJ·mol-1, 并建立了动力学方程; (Y, Gd)2O3∶Eu3+晶粒生长活化能是35.58 kJ·mol-1, 纳米粒子形核过程中的晶粒长大由晶界扩散控制.
关键词:
(Y, Gd)2O3∶Eu3+纳米粒子
,
synthesis kinetics
,
activation energy
,
micro-morphology
葛利芳
,
马伟民
,
魏明伟
,
周瑶
,
马雷
,
李军
功能材料
doi:10.3969/j.issn.1001-9731.2016.02.030
用反向共沉淀法合成Eu2Zr2O7/ZrO2(3Y)复相粒子;用XRD、DTA-TG、SEM表征物相变化及粒子形貌;分析了不同pH值下制备粉体的合成动力学.结果表明,两相体积比V (Eu2Zr2O7)∶V(ZrO2(3Y))=15∶85,初始溶液浓度0.1 mol/L,体系温度0℃,滴定速率2 mL/min,pH值=11,经1 100℃煅烧2.5h时,获得的Eu2Zr2O7/ZrO2(3Y)粒子形貌近似球形、粒径约35 nm.由Doyle-Ozawa和Kissinger法分别计算的pH值=11和12的样品物相变化各阶段的表观活化能平均值分别为59.66,100,310.53 kJ/mol和73.99,126.91,356.74 kJ/mol;晶粒生长活化能分别为18.96和23.90 kJ/mol,前者比后者小了4.94 kJ/mol,可见具有较高的烧结活性.
关键词:
反向共沉淀法
,
Eu2Zr2O7/ZrO2(3Y)粉体
,
pH值
,
合成动力学
,
表观活化能
TAN Aichun P/M Research Institute
,
Central-South University of Technology
,
Changsha
,
China.
材料科学技术（英）
The synthesis kinetics of YBa_2Cu_30_x supercon- ductor was studied through comparing the calcina- tion (sintering) processes of different kinds of powders. It was shown that the temperature of synthesis of YBa_2Cu_30_x phase can be lowered from 950℃ to 800℃ through direct calcination of multiphase powder with uniform chemical com- position. The stress which is caused by the volume change during synthetic reaction breaks the particles. It facilitates the formation of highly active superfines of superconductor.
关键词:
High T_c superconductor
,
null
,
null
,
null
