纳米钡铁氧体的制备与磁性研究  

Preparation and Magnetic Properties of Barium Hexaferrite Nanoparticles Prepared by Sol-Gel Method

作　　者：葛洪良[1] 陈强[1] 王新庆[1] 金红晓[1] 李良[1] 褚宁杰[1] 

机构地区：[1]中国计量学院材料科学与工程学院,浙江省磁学重点实验室,浙江杭州310018

出　　处：《稀有金属材料与工程》2008年第A02期440-444,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(20571067;10647149)资助的课题

摘　　要：采用溶胶凝胶法在不同pH值和煅烧温度条件下制备了M型纳米钡铁氧体样品,利用X射线衍射、场发射扫描电镜以及振动样品磁强计研究了溶液pH值和煅烧温度对纳米钡铁氧体的微结构和磁性能的影响。实验结果表明:溶液pH值及煅烧温度对钡铁氧体的相结构和磁性能都有很大影响。当溶液pH值在3以上时,有利于BaFe12O19相的形成,纳米钡铁氧体的晶粒尺寸约50nm,饱和磁化强度Ms和矫顽力Hc在pH=7时达到最高。对于pH=7的样品,在700℃左右开始有BaFe12O19相形成,同时伴有较多量的α-Fe2O3和少量的BaFe2O4与BaCO3杂相。随着温度的升高,BaFe12O19主相不断形成积累,杂相逐渐减少,当煅烧温度为800℃时,样品基本上为纯BaFe12O19相,经900℃热处理后样品磁性能最佳:饱和磁化强度达到Ms=61.6(A·m2)/kg,矫顽力为Hc=4.56×105A/m。Barium hexaferrite powders have been prepared using a sol-gel process under the different pH values and the different calcined temperatures. The influence of the pH value and the calcined temperature on the crystalline structure and the magnetic properties of barium hexaferrite were studied by XRD, FSEM and VSM. The experimental results show that the pH value of sol solution and the calcined temperature can obviously affect the crystalline structure and the magnetic properties of the as-prepared barium hexaferrite. It is positive for the formation of BaFe12O19 phase when pH value is above 3, the saturation magnetization Ms and coercivity Hc of the as-prepared barium hexaferrite nanoparticles with the uniform size of about 50 nm reach maximum at pH=7. Furthermore, the BaFe12O19 began to form at 700 ℃ with other phases such as α-Fe2O3, BaFe2O4 and BaCO3, with the increasing of the calcined temperature. The formation of BaFe12O19 phase went on, and finally the sample was pure BaFe12O19 phase when the calcined temperature arrived at 800 ℃. The barium hexaferrite sample calcined at 900℃ with the solution pH value of 7 exhibited the best magnetic properties： the saturation magnetization Ms = 61.6 （A.m2）/kg and the coercivity Hc = 4.56 × 10^5A/m.

关 键 词：钡铁氧体 PH值 煅烧温度 磁性能 

分 类 号：O482.5[理学—固体物理]