Effect of B 2O 3 and CuO additives on the sintering temperature and microwave dielectric properties of Ba(Mg 1/3Nb 2/3)O 3 ceramics

Abstract

B 2O 3 added Ba(Mg 1/3Nb 2/3)O 3 (BBMN) ceramics cannot be sintered below 930 °C. However, when CuO was added to them, they were sintered even at 850 °C. 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 ( ɛ 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 1/3Nb 2/3)O 3 + 2.0 mol% B 2O 3 + 10.0 mol% CuO ceramic sintered at 875 °C for 2 h, with values Q xf = 21 500 GHz, ɛ r = 31 and temperature coefficient of resonance frequency ( τ f) = 21.3 ppm/°C.