Ba(Zn_(1/3)Nb_(2/3))O_3-BaZrO_3系统结构和介电性能的研究

The Study on Structure and Dielectric Properties of Ba(Zn_(1/3)Nb_(2/3))O_3-BaZrO_3 System

研究了BaZrO3、MnCO3对Ba(Zn1/3Nb2/3)O3(BZN)系统结构和介电性能的影响。表明BaZrO3及Mn-CO3均能有效降低系统的烧结温度。系统中加入过多的BaZrO3(BZ)会降低介电常数,增大介质损耗,并使容量温度系数负向发展;加入微量MnCO3对系统的介电性能影响不大。系统中加入的x(BaZrO3)=4%会生成较多的第二相BaNb2O6、BaZrO3摩尔分数增加至8%时,第二相消失。这是由于过多BZ的加入会在烧结温度到达前生成较多液相,促进烧结的同时也阻碍了ZnO的挥发,从而抑制了第二相的生成。向96%BZN-4%BZ中加入r(MnCO3)=0.5%,也会抑制第二相的生成,这可能是由于Mn2+占据了B′位Zn2+挥发后留下的空位,形成固溶体,没有形成富Nb液相区,从而抑制了第二相的生成。

The effects of BaZrO_3,MnCO_3 on the structure and dielectric properties of Ba(Zn_(1/3)Nb_(2/3))O_3(BZN)-BaZrO_3(BZ)system are studied in this paper. It indicated that both BaZrO_3 and MnCO_3 can lower the sintering temperature of the system. Excess (BaZrO_3)8% in the system will decrease the dielectric constant,increase the dielectric loss and modulate the volume of temperature coefficient toward negative. Less MnCO_3 has little effect on the dielectric properties of Ba(Zn_(1/3)Nb_(2/3))O_3-BaZrO_3 system. That x(BaZrO_3)=4% is added to Ba(Zn_(1/3)Nb_(2/3))O_3 will cause more second phase(BaNb_2O_6),but when x(BaZrO_3)=8% is added to it,the second phase cann't be seen. Excess BaZrO_3 can lower the second phase of the system by the appearance of liquid phase before the arising of the sintering temperature and suppress the volatilization of ZnO,thus inhibit the presence of the second phase. That r(MnCO_3)=0.5% is added to BZN-0.04%BZ will inhibit the presence of the second phase,too. Probably,Mn^(2+) takes place of the vacancy caused by the volatilization of ZnO and creates solid solution instead of niobium-rich liquid phase,then inhibit the presence of the second phase.