Fablicaion of Lamellar- and Cell-Structured α-Fe/Fe_3O_4 Complex Particles and Their Application to Magnetic Material and Catalysis

研究了层状结构的α-Fe/Fe_3O_4复合粒子和胞状结构的Fe_3O_4粒子对磁性材料和催化性能的影响：(1)维氏体粉的制备和表征：通过机械合金化的α-Fe粉末和Fe_3O_4商用粉末的陈化和冷却，实现了维氏体粉的制备和表征。通过X射线衍射、热分析、穆斯堡尔谱和磁测量等手段对其晶体结构、热稳定性和磁性进行了研究。(2)层状结构α-Fe/Fe_3O_4复合粒子的热分解可以得到层状结构的α-Fe/Fe_3O_4复合粒子。颗粒尺寸为几十微米，由20纳米α铁和60纳米磁铁矿组成，如LOD。(3)晶胞结构Fe_3O_4粒子的制备：通过硝酸刻蚀α-Fe/Fe_3O_4复合粒子中的α-Fe组分，可以得到晶胞结构的Fe_3O_4粒子。(4)对Ni-Co-Wusite系统的研究，由于Ni-Co-Wusite相在高温下不稳定，不能得到像Ni/Ni_3O_4和Co/Co_3O_4这样复杂的晶胞结构粒子。结果表明，制备α-Fe/CoFe_2O_4和α-Fe/NiFe_2O_4复合粒子时，推荐使用Fe(Co)O或Fe(Ni)O黄铁矿。

The authors studied the shnthsis of lamellar-structured α-Fe/Fe_3O_4 complex particle and cell structured Fe_3O_4 particle to magnetic material and catalysis.(1) Fabrication and cahacterization of wustite ; Wustite powder could be fablicated by anneling and cooling of mechanically alloyed α-Fe powder and Fe_3O_4 commercial powder. Their crystal structure and thermal stability and magnetic property were studied using by X-ray diffraction, thermal analysis, Mossbauer spectroscopy and magnetic measurement.(2) Fablication of lamellar-structured α-Fe/Fe_3O_4 complex particle ; Lamellar-stuctured α-Fe/Fe_3O_4 complex particle could be obtained by thermal decomposition of wustite powder mentioned above. The size of particle was several tens of micron meter, and it was constructed of 20 nanometer α-iron and 60 nanometer magnetite components like lod. It showed ferromagnetic with saturation magnetization of 96 emu/g, but the siperparamagnetism was not observed.(3) Fabrication of cell structured Fe_3O_4 particle ; Cell-structed Fe_3O_4 particle could be obtained by etching out of α-Fe component from α-Fe/Fe_3O_4 complex particle using nitric acid.(4) investigation to Ni-and Co-wustite system ; It was not able to obtain complex and cell-structured particle as Ni/Ni_3O_4 and Co/Co_3O_4, because Ni- and Co-wustite were stable up to high temperature. It was suggested that Fe (Co) O or Fe (Ni) O wustite was recommended to obtain α-Fe/CoFe_2O_4 and α-Fe/NiFe_2O_4 complex particle.