水热法制备BiFeO_3粉体

Hydrothermal Synthesis of BiFeO_3 Powders

以FeC l3.6H2O和B i(NO3)3.5H2O为原料,氨水为沉淀剂,KOH为矿化剂,采用共沉淀法制备前驱物,水热法合成了纯相的B iFeO3粉体。X射线衍射结果表明,在160℃,碱浓度仅为0.15 mol/L的水热条件下,即可合成纯相的B iFeO3粉体。该工艺大大降低了水热温度,减小了碱浓度,从而节约了能源,降低了成本,减轻了碱对水热设备的腐蚀。扫描电镜显示,前驱沉淀物陈化时间为1 d时,水热制备的B iFeO3粉体中有发育良好的六方短柱状晶体形成;陈化时间增加到3 d时,所得B iFeO3粉体呈双层板状。差热-失重分析表明,所得B iFeO3粉体的尼尔温度(TN)为301℃,居里温度(TC)为828℃,分解温度为964℃。

A series of pure phase BiFeO3 powders were prepared by co-precipitation and hydrothermal reaction using FeCl3 · 6H2O and Bi（ NO3 ）3 · 5H2O as starting materials,ammonia as precipitant and KOH as mineralizer. XRD results indicated that single-phase BiFeO3 powders could be fabricated via hydrothermal method at 160 ℃ with KOH of only 0. 15 mol/L. Therefore when this technique was adopted,hydrothermal reaction temperature and the concentration of KOH could be sharply brought down to save the energy and material cost and weaken the corrosion of eguipment. SEM images revealed that when the precipitated precursor was aged for 1 d, thee were short hexagonal columnar crystals in the synthesized BiFeO3 powders;when the aging time was extended to 3 d, the synthesized BiFeO3 powders were double-layered sheets. DSC -TG analysis showed that Néel temperature （TN ）, Curie temperature（ Tc ） and decomposition temperature were 301,828 and 964 ℃ respectively.