液相热分解纳米铁镍合金的形貌可控合成及其磁学性能研究

摘要

Fe-Ni alloy nanoparticles were synthesized by thermal decomposition of Ni(COOH)_2 and Fe(CO)_5 with 1-octadecene as the solvent and oleic acid (OA) and oleylamine(OLA) as surfactants. The produced Fe-Ni alloy nanoparticles were characterized by X-ray diffraction(XRD), transmission electron microscope(TEM) and vibrating sample magnetometer(VSM). The results showed that a shape controlled fcc phase Fe-Ni alloy nanoparticles of triangular shape was formed when the molar ratio, of OA, OLA and Ni(HCOO)_2 was 4:2:1 at 200 ℃ fo 20 min. Magnetic measurements revealed the alloy nanoparticles of triangular shape exhibit superparamagnetic behavior with a saturation magnetization of 15.5 emu·g~(-1) at 300 K; a saturation magnetization of 17.5 emu·g~(-1) and a coer-civity of 158 Oe at 4.2 K.%以Fe(CO)_5和Ni(HCOO)_2为前驱物,十八烯为溶剂,在表面活性剂和分散剂油酸和油胺的协同作用下,通过前驱体的液相热分解和自合金化,制备铁镍合金纳米颗粒.通过XRD和TEM研究了产物的微观结构.并对产物的磁学性质进行了表征.结果表明,在反应温度为200℃,油胺与油酸及甲酸镍的物质的量比为4:2:1,反应时间为20 min时可得形貌可控、抗氧化性强的面心立方晶体结构的平面三角形纳米铁镍合金,晶粒尺寸为15～55 nm.磁性测量表明,300 K时三角形形貌铁镍合金的饱和磁化强度为15.5 emu·g~(-1),矫顽力趋近于零,呈现超顺磁性;在低温(4.2 K)时,铁镍合金的饱和磁化强度为17.5 emu·g~(-1),矫顽力增大明显.