化学共沉淀法制备单相BiFeO_3粉体及其高密度单相陶瓷块材的物理性能

Preparation of Single Phase BiFeO_3 Powders by Co-precipitation Method and Physical Properties of Single Phase BiFeO_3 Ceramics with High Density

通过对Fe3＋-Bi3＋-NO-3-H2O体系的热力学分析,确定了Bi3＋、Fe3＋共沉淀范围为p H=7~12。固定p H=11,采用共沉淀法制备了Bi Fe O3的前驱体,经过煅烧得到了单相Bi Fe O3粉体,并进行了粒度和晶体结构的研究。采用放电等离子烧结（spark plasma sintering,SPS）的方法制备出高密度单相Bi Fe O3陶瓷块材并测试了其介电性能和铁电性能。结果表明,陶瓷块材相对密度为96.7%;陶瓷块材在频率为30 MHz时,介电常数ε＇为91.9,介电损耗tanδ为0.017;陶瓷块材在室温时具有铁电性。在电场强度为30 k V/cm时,饱和极化强度Ps＇=0.40μC/cm2,剩余极化强度Pr＇=0.17μC/cm2,矫顽场强度EC=16 k V/cm。放电等离子烧结（SPS）出的陶瓷块材比传统常压烧结制备的陶瓷块材更加致密,介电和铁电性能更加优良。

Through thermodynamic analysis for Fe3 ＋-Bi3 ＋-NO-3-H2 O system,it determined that the range of the co-precipitation of Fe3 ＋-Bi3 ＋ions was p H = 7-12. Then precursor powders was prepared by coprecipitation method fixed p H at 11. After precursor powders was calcined,the pure phase of Bi Fe O3 powders was obtained. The particle size,distribution and crystal structure of Bi Fe O3 were researched.Single phase Bi Fe O3 ceramics with high density were prepared by spark plasma sintering（ SPS） and then dielectric properties and ferroelectric properties of ceramics were investigated. The results show： the relative density of ceramics is 96. 7%; the dielectric constant of ceramics is 91. 9 and the dielectric loss of ceramics is 0. 017 at a frequency of 30 MHz; ceramics show ferroelectric properties at room temperature. When the electrical field intensity is 30 k V / cm,saturation polarization Ps＇ = 0. 40 μC / cm2;remanent polarization Pr＇ = 0. 17 μC / cm2; coercive force EC= 16 k V / cm. Ceramics prepared by spark plasma sintering is more compacted than that prepared by conventional presureless sintering and dielectric properties and ferroelectric properties of ceramics prepared by spark plasma sintering is better.