莫来石单相胶前驱体结晶动力学  

Crystallization kinetics of mullite from single-phase gel

作　　者：张桂敏[1] 陈阳波 傅正义[3] 王玉成[3] 任琳[3] 

机构地区：[1]武汉理工大学理学院化学系,湖北武汉430070 [2]武汉尚远环保技术有限公司,湖北武汉430070 [3]武汉理工大学复合材料新技术国家重点实验室,湖北武汉430070

出　　处：《功能材料》2013年第24期3571-3575,共5页Journal of Functional Materials

基　　金：中央高校基本科研业务费专项资金资助项目(2011-1a-031);国家自然科学基金A3前瞻计划资助项目(51161140399)

摘　　要：用非等温热分析法研究了莫来石单相胶前驱体的结晶动力学,采用XRD、TEM和27 Al-NMR分析了前驱体向莫来石转化的微观结构变化。结果表明,前驱体在950℃开始形成莫来石晶体,结晶过程为以Avrami-Erofeev的随机形核和随后生长机制,动力学三因子:活化能Ea=1 086.34kJ/mol,指前因子A=9.33×1042s-1,机理函数的微分表达式f(α)=n(1-α)[-ln(1-α)],其中n=3.37。结晶动力学为非均匀形核过程,形核速率I随时间t而下降;980℃左右主要以形核控制为主,1 000℃左右则以核生长控制为主,晶粒的长大为扩散控制长大机制。The crystallization kinetics of mullite from single-phase gel were studied using a non-isothermal ther-mal analysis method.The microstructure changes were investigated by X-ray power diffraction （XRD）,trans-mission electron microscopy （TEM）and 27 Al nuclear magnetic resonance （NMR）spectroscopy.The results show mullite crystallization begins from 950 ℃.The crystallization process confroms to random nuclei produc-tion and the following unclei growth model of n-dimension Avrami-Erofeev.The activation energy Ea and the pre-exponential factor A of mullite crystallization are 1 086.34 kJ/mol and 9.33×1042 s-1,respectively.The differential expression of the corresponding mechanism function was f （α）=n（1-α）[-ln（1-α）] n-1 n ,n=3.37.The nucleation rates are non-uniform which decrease with the time t in crystallization process.Nuclea-tion was the dominant controlling step at about 980 ℃.Nucleation-growth becomes more predominant at about 1 000 ℃.The rates of the grain growth are controlled by diffusion.

关 键 词：莫来石单相胶 结晶动力学 非等温热分析 速率控制步骤 

分 类 号：O643.12[理学—物理化学]