Influence of BaZrO_3, MnCO_3 Additives on Dielectric Properties and Microstructure of Ba(Zn_(1/3)Nb_(2/3))O_3 Ceramics and Ba(Zn_(1/3)Nb_(2/3))O_3-Sr(Zn_(1/3)Nb_(2/3))O_3 Solid Solutions

摘要

The effect of BaZrO_3, MnCO_3 additives on the dielectric properties, sintering temperature and microstructure of Ba(Zn_(1/3)Nb_(2/3))O_3 (BZN) and Ba(Zn_(1/3)Nb_(2/3))O_3- Sr(Zn_(1/3)Nb_(2/3))O_3 (BSZN) ceramics was studied in this paper. It indicates that both BaZrO_3 and MnCO_3 can lower the sintering temperature of the ceramics and accelerate the crystallization of BZN and BSZN. The dielectric constant ε_r increases after MnCO_3 added, but decreases when BaZrO_3 added alone. The existence of MnCO_3 can modulate the temperature coefficient of capacitance τ_c toward positive, while BaZrO_3, can make c more negative. MnCO_3 and BaZrO_3 can restrain the appearance of the second phase; while BaZrO_3, can prevent the appearance of the superstructure. In the BSZN system, when 1 mass % MnCO_3 added, sintering temperature(t_s) is lowered to 1240℃. In this study, the best sample that has the excellent properties is sample 5 with dielectric properties of ε_r= 43.6, τ_c =-8×10~(-6)℃~(-1) and tan δ = 0.6×10~(-4) (1 MHz). The sintering temperature of BZN and BSZN system can be lowered to less than 1300℃.