(Y,Gd)_2O_3:Eu^(3+)纳米粒子制备过程中的合成动力学

SYNTHESIS KINETICS OF(Y,Gd)_2O_3:Eu^(3+) NANOPOWDERS DURING PROCESS OF PREPARATION

采用反向滴定共沉淀法制备出(Y,Gd)_2O_3:Eu^(3+)前躯体,再在不同温度下煅烧,获得(Y,Gd)_2O_3:Eu^(3+)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获得了佯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)_2O_3:Eu^(3+)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.

Using NH_3·H_2O and NH4HCO3 blended solution as a complex precipitation agent, （Y,Gd）_2O_3：Eu^（3＋） nano-particles were synthesized by co-precipitation reaction.XRD and SEM were applied to analyze the crystallization and morphology of the sample.The thermal decomposition curves of samples were analysed by TG-DTA at different heating rates.Results showed that under the conditions of pH=10 and reverse titration,the change process of（Y,Gd）_2O_3：Eu^（3＋） precursors is divided into three steps.The apparent activation energy of each step was calculated by using the Doyle-Ozawa and Kissinger methods.The calculated results are 191.54,557.05 and 236.58 kJ-mol^（-1）. The dynamic equations have been also established.The activation energy of（Y,Gd）_2O_3：Eu^（3＋）grain growth is 35.58 kJ-mol^（-1）,indicating that grain growing is primarily controlled by interfacial reaction during process of preparation.