【作者】 刘秋艳；

【导师】 温鸣；

【作者基本信息】 同济大学 ， 无机化学， 2008， 硕士

【摘要】 本文通过正相微乳液法制备出不同成分配比的Co-Ni-Cu体系非晶态合金磁性纳米粒子,并对反应机理进行了分析和讨论。采用油酸及油酸钠作为表面活性剂,配制出稳定性好、油滴分布均匀的正相微乳液,成功地制备出Co-Ni-Cu体系的非晶态合金磁性纳米粒子。所得产物为单分散性优异的球形合金纳米颗粒,粒径在4～7nm之间,粒径小且粒径分布较窄。XRD及选区电子衍射结果表明Co-Ni-Cu体系合金纳米粒子处于非晶态,经回火热处理后,非晶态合金纳米粒子转化为具有FCC结构的晶态合金,并伴有热量的放出,这与DSC曲线上样品S2在630.5K和649.8K出现的放热峰、S5在647.1K出现的放热峰、S6在652.8K和697.5K出现的放热峰、S7在641.6K和709.5K出现的放热峰结果相一致。VSM磁性测试结果表明制备的非晶态合金纳米粒子的矫顽力小,经回火热处理后,随着晶型的转化,部分样品的矫顽力和饱和磁化强度均有显著的增大,表现出优良的软磁性能。另外,我们还采用表面活性剂油酸和Tween-80复配的正相微乳液来合成非晶态合金纳米粒子。由于两种表面活性剂的协同作用,增强了微乳液油水界面膜的强度,使得微乳液的性能更稳定,同时在对纳米粒子的表面改性方面具有更好的包覆作用,从而制备出了粒径均一,分散性能更好的Co-Ni-Cu体系非晶态合金纳米粒子。更多还原

【Abstract】 Using oleic aciad and sodium oleate as surfactant, the positive microemulsion with excellent properties was formed and studied. Then, the monodisperse Co-Ni-Cu amorphous alloy magnetic nanoparticles were synthesized in positive microemulsion (hexane/oleic acid and sodium oleate/water) system mentioned above. TEM results show that the as synthesized particles are spherical alloy nanoparticles with the size of 4～7nm in narrow deviation. The XRD and SADP patterns proved that the structure of the as-synthesized Co-Ni-Cu alloy nanoparticles are amorphous state. After annealing, the structure of the amorphous alloys was changed to the crystal state with FCC structure. The exothermic peaks of S2 at 630.5K and 649.8K、S5 at 647.1K、S6 at 652.8K and 697.5K, S7 at 641.6K and 709.5K in the DSC patterns were observed due to the crystallization process. The magnetization behavior was studied by vibrating sample magnetometer (VSM). The results showed that the as synthesized Co-Ni-Cu amorphous alloy nanoparticles had small covercivity. After annealing, the saturation magnetization and coercivity of some samples increased significantly. It was correspond to the crystallization of amorphous alloy nanoparticles.The formation of the microemulsion employed oleic acid and Tween-80 as mixed-surfactants was also studied and the appropriate formed condition of the microemulsion was found. Using the mixed-surfactants to synthesize Co-Ni-Cu amorphous alloy nanoparticles, the nanoparticles with more uniform diametre, more well-dispersion and more excellent stability were abtained.更多还原