Morphological evolution of tridymite crystal in SrO-BaO-Nb2O5-CaO-SiO2-B2O3 ferroelectric glass-ceramic

In order to increase the breakdown strength of ferroelectric glass-ceramic, morphological control of tridymite in SrO-BaO-Nb2O5-CaO-SiO2-B2O3 glass-ceramic is achieved by adjustment of annealing temperature. Annealed at 600-650 °C, round tridymite crystal can be obtained using Cr2O3 as the nucleating agent, whereas flowerlike tridymite crystal would be formed after annealing at the temperatures of 700-800 °C. With XRD, SEM and EDS analyses, a crystallization model is used to explain the morphological feature change. Because of more SiO2 keeping as amorphous phase, the breakdown strength of the ferroelectric glass-ceramic with round morphological feature of tridymite crystal can be increased. The results have indicated that the annealing processes have a great impact on the composition of the glass-ceramic hosting tridymite crystal and morphological feature of tridymite.