科研之友
微信
新浪微博
Facebook
分享链接
摘要
The effect of powder particle size on non-isothermal crystallization kinetics of Ge11Ga11Te78 glass was examined by differential scanning calorimetry. Multivariate kinetic analysis was used to deconvolute the complex crystallization data. The overall process was found to be composed of initial tellurium precipitation followed by simultaneous formation of Ga2Te5 and GeTe phases. While the Te precipitation followed the nucleation growth Johnson-Mehl-Avrami kinetics with the growth originating mainly from surface and mechanically induced defects, the formation of gallium and germanium tellurides proceeded autocatalytically with a significantly lower involvement of the defects-based crystal growth. The model-based part of the kinetic behavior was found to be uninfluenced by the change in powder coarseness-both crystallization sub-processes were described in terms of similar models with similar kinetic exponents for all particle size fractions. On the other hand, the model-free kinetic parameters (activation energies, pre-exponential factors and crystallization enthalpies) were found to be significantly changing with increasing particle size; the observed trends were explained in terms of the changing amounts of the two involved types of crystallization centers.
- 出版日期2017-7
