Low Temperature Sintering and Dieletric Properties of $Sr_2Nb_2O_{7}$ Ceramics by the Flux and the Chemical Coprecipitation Methods

용융염합성법과 화학공침법에 의한 $A_2B_2O_{7}$형 압전세라믹스의 저온소성과 유전특성

Strontium niobate, $Sr_2Nb_2O_{7}$ was prepared by the molten stilt synthesis (MSS) and the chemical coprecipitation method (CCP). Single phase $Sr_2Nb_2O_{7}$ was obtained by MSS and CCP at $750^{\circ}C$ and $800^{\circ}C$, respectively. An intermediate phase of composition, $Sr_{5}Nb_4O_{15}$, appeared at $700^{\circ}C$ when CCP method was employed. The resulting powder was observed to have finer particles and more uniform distribution of particle sizes, as compared to those obtained through the conventional method. Such powder characteristics allowed the use of a much lower sintering temperature of $1400^{\circ}C$. Grain-orientation along (0k0) direction, which is advantageous for improving dielectric properties, was also observed. The sintering characteristics and the dielectric properties prepared by MSS and CCP, were better than those by the conventional method.