聚丙烯酰胺凝胶法合成BiFeO_3纳米颗粒

Synthesis of BiFeO_3 Nanoparticles by a Polyacrylamide Gel Route

采用一种新的聚丙烯酰胺凝胶法制备了BiFeO3纳米颗粒.以无机盐溶液为原料,通过加入丙烯酰胺使溶液成胶;在溶液成胶过程中,丙烯酰胺聚合形成高分子网络骨架,为粒子提供生长的空间.实验表明,以EDTA作为络合剂可以获得高纯BiFeO3粉体.同时发现,在前驱体溶液中添加适量的葡萄糖,可有效抑制凝胶体在干燥过程中发生剧烈塌缩,对提高粉体的质量起到重要作用.SEM观察显示,制得的BiFeO3粉体的粒度分布均匀,颗粒近似呈球形,颗粒间无粘连团聚现象.DSC分析表明,样品的反铁磁和铁电相变温度分别为370和830℃.电滞回线和磁滞回线测量结果表明,样品在室温下具有明显的铁电性和弱铁磁性.

A new polyacrylamide gel route was used to prepare BiFeO3 nanoparticles.In this route,the solution containing the required cations was gelled by using acrylamide;during the gelation process,acrylamide was polymerized to form a polymer network,which provided a structural framework for the growth of particles.It is demonstrated that high-purity BiFeO3 powders can be prepared using ethylenediamine-tetraacetic acid（EDTA） as the chelating agent.On the other hand,it is found that adding an appropriate amount of glucose to the precursor solution can effectively suppress the gel shrinkage during drying,and consequently lead to a significant improvement of powder quality.Scanning electron microscope（SEM） observation reveals that the as-prepared BiFeO3 powder has a uniform particle size,and the particles are almost spherical without any agglomeration or adhesion.Differential scanning calorimetry（DSC） analysis reveals that the product has an antiferromagnetic phase transition at about 370℃ and a ferroelectric phase transition at about 830℃.Ferroelectric and magnetic hysteresis loop measurements show that the product exhibits clear ferroelectric property and weak ferromagnetism.