Ag2O机械活化和热还原合成Ag的等温动力学

摘要

The kinetics of isothermal reduction of Ag2O with graphite under argon atmosphere for a non-activated sample and mechanically activated sample was investigated.It is found that Johnson-Mehl-Avrami model appropriately explained the thermal and mechanochemical synthesis of Ag from Ag2O+ghraphite mixture.The process kinetics was investigated using the same approach for milled and unmilled samples.The results show that the Avrami exponent of mechanochemical reduction is higher than that of high temperature thermal reduction.Also,the mechanisms of nuclei growth in thermal and mechanochemieal reduction are diffusion controlled and interface controlled,respectively.%在氩气气氛下,将Ag2O与石墨通过机械活化或热还原反应生成Ag,对其等温还原过程的动力学进行研究.结果表明,采用Johnson-Mehl-Avrami模型能合理地解释Ag2O与石墨经机械活化和热还原合成Ag的过程.采用相同的模型来研究机械活化和热还原反应合成Ag的动力学时,机械活化还原过程中的Avrami指数比热还原的要高；热还原和机械活化过程中的晶核长大机制分别是扩散控制和界面控制.