α-FeOOH脱水过程后期的封孔机制

Mechanism of Micropore Disappearing in the Later Period ofα-FeOOH Dehydration

采用Ｇｅｒｍａｎ和Ｍｕｎｉｒ提出的烧结动力学，对文题进行了研究。结果表明，在α－ＦｅＯＯＨ分解成ａ－Ｆｅ２Ｏ３的过程中，随着温度升高，产生的孔洞通过颗粒内部的晶核表面扩散的烧结机制逐渐消失。对于包敷ＳｉＯ２的样品，相应的烧结活化能增加。当焙烧温度太高，会出现颗粒之间彼此烧结，并且未包敷的样品更易烧结。

The mechanism of the micropore disappearing in the later period of α-FeOOH dehydration has been investigated using a sintering kinetics presented by German and Munir.The result shows that in the process of α-FeOOH decomposing to a-Fe2O3,the formed micropore gradually disappeares via a surface diffusion of the crystal nucleus within particles against the temperature increasing. In the case of coating SiO2,the sintering activation energy increases. If the calcination temperature is too high,the sintering of each particles occurs, and the sample without coating is much easy to be sintered.