Kinetic Behavior of the Nonisothermal Crystallization of Highly Refracted Glass Microspheres

Abstract

The SiO2–TiO2–BaO (STB) system glasses were prepared by the melt-quenching technique. The crystallization kinetics of the STB glasses were studied by the kinetic modeling of Kissinger and Augis–Bennett equations in combination with complementary characterization methods such as X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), IR, and Raman. The crystallization of Ba2TiSi2O8 was observed during the heat treatment process. The crystallization activation energy of Ba2TiSi2O8 is Ep = 207.64 kJ/mol. The average crystallization index is n = 1.14, suggesting a mechanism of surface nucleation in one-dimensional space. Glass microspheres (GMSs) made from the given STB glasses are prone to crystallization during the spheroidization process, and the consequent surface nucleation reduced the brightness of GMSs. By adjusting the spheroidization from 2 to 0.8 s, the brightness increased from 52 to 63 cd*1 x–1 m–2. In addition, it was found that the higher BaO content of the STB glasses facilitated the observed surface nucleation.