关键词: 有机凝胶先驱体转化法, M-Sr铁氧体, 中空纤维, 可纺性, 磁性能

Abstract:

The Mtype strontium ferrite （SrFe₁₂O₁₉） hollow fibers were prepared by the organic gel-precursor transformation method using citric acid and metal salts as raw materials. The gel-precursors and the as-prepared fibers were characterized by FTIR, XRD, TG/DSC, SEM and VSM. The results show that the gel spinnability is related with the chemical composition and pH value. The gel exhibits an appropriate spinning performance when the molar ratio of citric acid to the total metal ions is 1.5∶1.0 and the pH value is around 4.2. The M-type strontium ferrite hollow fibers obtained are characterized with high aspect ratio, thin diameters and ratio of the hollow diameter to the fiber diameter being about 1/2.The fibers calcined at 1100℃ are composed of SrFe₁₂O₁₉ nanoparticles with hexagonal plate morphology and average particle size of about several hundred nanometers. At room temperature, the saturation magnetization and coercivity of the M-type strontium ferrite hollow fibers calcined at 1100℃ are 53.5A·m²/kg and 386.96kA/m, respectively. These M-type strontium ferrite hollow fibers possess a shape anisotropy characteristic and the coercivity for the aligned hollow fibers parallel and parpendicular to the applied field is correspondingly 391.66kA/m and 358.72kA/m.

Key words: organic gel precursor transformation method, M-Sr ferrite, hollow fibers, spinnability, magnetic properties