Nucleation and Growth of Nanocrystals in Glass‐Ceramics: An In Situ SANS Perspective
We studied the nucleation and growth of nano‐sized crystals on two glass‐ceramic systems: a conventional lithium‐aluminosilicate (LAS) and a (Mg,Zn) spinel.
We combined several techniques: in situ Small Angle Neutron Scattering (SANS), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), and laboratory X‐ray diffraction (XRD).
We observed by SANS, and confirmed by DSC, that during a temperature ramp, transient phenomena occur between the regions of nucleation and growth in the LAS, which do not follow classic kinetic theories. In contrast, the spinel
material shows a smooth transition during the temperature ramp between the nucleation and the growth stages, and follows a more conventional growth pattern. In the spinel system the initial phase separation plays a very important role in determining the crystalline phase distribution in the
glassy matrix, as crystallites are confined only in one phase.