Effect of B_2O_3 and CuO additives on the sintering temperature and microwave dielectric properties of Ba(Mg_(1/3)Nb_(2/3))O_3 ceramics

摘要

B_2O_3 added Ba(Mg_(1/3)Nb_(2/3))O_3 (BBMN) ceramics cannot be sintered below 930℃. However, when CuO was added to them, they were sintered even at 850℃. The amount of the Ba_2B_2O_5 second phase, which was formed in the BBMN ceramics decreased with the addition of CuO. Therefore, the CuO additive is considered to react with the B_2O_3 inhibiting the reaction between B_2O_3 and BaO. A dense microstructure without pores developed with the addition of a small amount of CuO. The bulk density, dielectric constant (ε_r) and Q-value increased with the addition of CuO, but decreased when a large amount of CuO was added. Excellent microwave dielectric properties were obtained for the Ba(Mg_(1/3)Nb_(2/3))O_3 + 2.0 mol% B_2O_3 + 10.0 mol% CuO ceramic sintered at 875℃ for 2 h, with values Q_(xf) = 21 500 GHz, ε_r = 31 and temperature coefficient of resonance frequency (τ_f) = 21.3 ppm/℃.