Effect of B2O3 on the microstructure and microwave dielectric properties of Ba(Mg1/3Nb2/3)O3 ceramics

Abstract

The in uences of different doping contents of additive B 2 O 3 on the sintering behavior, microstructure and microwave properties of Ba(Mg 1/3 Nb 2/3 )O 3 (BMN) microwave ceramics were studied. The main phase in the sintered ceramics was crystallized as Ba(Mg 1/3 Nb 2/3 )O 3 (BMN). Ba 2 B 2 O 5 as secondary phase was observed with x ≥ 10. Scanning electron microscopy (SEM) analysis revealed that the photograph of optimally nonstoichiometric ceramics sintered at 900 ℃ for 5 h displayed a dense microstructure. The dielectric properties and microstructures of BMN ceramics were very sensitive to the nonstoichiometry.The addition of B 2 O 3 had a positive in uence on the Q×f value, for example the sample with x = 7 showed the highest Q×f value of 89800 GHz. Finally, excellent microwave dielectric properties (ε r = 31.6, Q×f = 89,800 GHz and τ f = 3.6 ppm/℃) were achieved for the sample with x = 7 sintered at 900 ℃ for 5 h.