CRYSTALLIZATION BEHAVIOR OF FERROELECTRIC GLASS-CERAMICS OF THE Na2O-Nb2O5-Al2O3-SiO2 SYSTEM CONTAINED TiO2

The ferroelectric glass-ceramic of the composition Na(2)O-Nb(2)O(5)-Al(2)O(3)-SiO(2) was prepared by controlling crystallization of the glass that added with small amount of TiO(2). The effect of TiO(2) content on crystallization behavior and the dielectric property were determined. X-ray diffraction studied indicated that NaNbO(3), NaNbO(8) and a compound of alkali alumino silicate composition were readily formed in the as-quenched glass as the product of phase separation. After treatment at 700 degrees C for various times, NaNbO(3) volume fraction was found to increase with time. Crystalline size of the NaNbO(3) was lower than 300 nm and it was developed with treatment time. Presence of TiO(2) had considerably effect on NaNbO(3) volume fraction when treatment time shorter than 1.0 h. The dielectric response of the glass-ceramic samples was found to arise from all contributions of crystalline phases and glass matrix responds.