B2O3 additives on sintering and microwave dielectric behaviors of Mg4Nb2O9 ceramics synthesized through the aqueous sol-gel Process

The relationships between the sintering temperatures and the microwave dielectric properties of (1-x)Mg4Nb2O9-xB(2)O(3) (x = 0.5-10 wt. %) compounds were investigated by the sol-gel method in order to reduce the sintering temperature in this study. A suitable amount of B2O3 doping was effective in allowing low sintering temperatures without a little detrimental effect on these dielectric properties of the Mg4Nb2O9 compounds. The variations in the dielectric constant (epsilon (r) ) and the quality factor (Q center dot f) of the Mg4Nb2O9 compounds depended on the amount of B2O3 doping and the sintering temperature. As a result, a epsilon (r) value of similar to 12.8 and a Q center dot f value of similar to 142,570 GHz were obtained when the Mg4Nb2O9 compound with x = 3% was sintered at 1,200 A degrees C for 4 h. The temperature coefficient of resonant frequency (tau (f) ) of the 3%-B2O3 doping Mg4Nb2O9 compound slightly changed from -33 to -48 ppm/A degrees C with an increased sintering temperature.