摘要
利用溶胶-凝胶自燃烧高温合成法制备了稀土 La 掺杂钡铁氧体 BaLa0.3Fe11.7O19 纳米粉末。用 X 射线衍射仪、振动样品磁强计和透射电镜对不同溶胶组成下合成的粉末的结构、磁学性能、粒度及形貌进行了研究。试验表明:用氨水调节溶液起始 pH 值以及加入适量的柠檬酸和乙二醇是合成结构纯净、性能优异的 BaLa0.3Fe11.7O19 纳米粉末的 2 个关键步骤。在溶液起始 pH 值呈弱酸性(7.0 左右)、柠檬酸/硝酸盐=3、煅烧温度为 850℃,保温 1 h 的条件下, 利用溶胶-凝胶自燃烧高温合成法可以制备出粒径为 36 nm 的磁铅石结构的 BaLa0.3Fe11.7O19 粉末,其磁学性能优异,比饱和磁化强度可达 65.54 A·m2/kg,矫顽力可达 433 kA/m。
The hexagonal BaLa0.3Fe11.7O19 Ultrafine powders with a magnetoplumbite type (M-type) structure were synthesized with process of self-propagating high temperature synthesis (SHS) of sol-gel. The precursor solutions with different composition were investigated to clarify the forming conditions of the ferrites. The crystal structure, grain size, form and magnetic properties were studied by means of X-ray diffraction (XRD), transmission electronic microscope (TEM) and vibrating sample magnetometer (VSM). On the basis of analysing the effect of ammonia, citric acid and glycol on phase structure and magnetic properties, it was demonstrated that adjusting the pH value of precursor solution with ammonia and adding the proper amount of citric acid and glycol are key steps in synthesis of ultrafine powders with single BaFe12O19 phase and excellent magnetic properties. In the presence of chelate agent (citric acid) and dispersant (glycol), under the conditions of PH about 7.0, nitrate/citric acid molar ratio of 1:3 and calcination temperature of 850degreesC(1h), M-type BaLa0.3Fe11.7O19 ultrafine powders with a particle size about 36 nm, a specific magnetization delta(s) of 65.54 A . m(2)/kg and a coercive force (j)Hc of 433 kA/m, was obtained.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2004年第11期1165-1169,共5页
Rare Metal Materials and Engineering
关键词
溶胶
凝胶法
稀土
永磁铁氧体
柠檬酸
sol-gel method
rare earth element
permanent magnetic ferrite
citrate
