Crystallization Kinetics of Nanophase Glass-Ceramics as Magnetic Disk Substrate

摘要

Glass-ceramics containing beta-quartz as a main crystal phase based on the system of SiO_2-Al_2O_3-Li_2O-K_2O-MgO-ZnO were investigated for the application to magnetic storage substrate for higher storage capacity. Parent glasses were prepared, then nucleated and crystallized at certain temperatures for 3 approx 4 h. The crys-tallization kinetics of glass-ceramics was also studied. The grain size was estimated by Scherrer formula and image treatment of transmission electron microscopy (TEM). The results showed that the Avrami exponent was determined to be 3.88, the activation energy 189.3 + - 7 kJ/mol and the grain size 30 approx 60 nm. A detailed microstructure of the glass-ceramics, including grain distribution and the morphology of nano-crystalline was characterized by TEM, X-ray diffraction (XRD), differential scanning calorimeter (DSC), differential thermal analysis (DTA). The relationship between microstructure and mechanical properties was also discussed.