A TEM study and non-isothermal crystallization kinetic of tellurite glass-ceramics

The glass transition temperature was studied via differential thermal analysis of glasses in the system (100 − x )TeO 2 –5Bi 2 O 3 – x ZnO and (100 − x )TeO 2 –10Bi 2 O 3 – x ZnO where x = 15, 20, 25 in mol%. The crystallization behavior and microstructure development of the 0.7TeO 2 /0.1Bi 2 O 3 /0.2ZnO glass during annealing were investigated by non-isothermal differential thermal analysis (DTA), X-ray diffractometry, and transmission electron microscopy. The glass transition temperature, crystallization temperature, and the nature of crystalline phases formed were determined. From the heating rate dependence of the glass transition temperature, the glass transition activation energy was derived. From variation of DTA peak maximum temperature with heating rate, the activation energies of crystallization were calculated to be 305.8 and 197 kJ mol −1 for first and second crystallization exotherms, respectively. Moreover, synthesized crystalline Bi 3.2 Te 0.8 O 6.4 , Bi 2 Te 4 O 11 , and Zn 2 Te 3 O 8 were investigated. In addition, the change in particle size with increasing annealing time was observed by high-polarized optical microscope.