高饱和磁化强度磁性碳纳米管的制备与性能研究

发布时间：2018-04-22 22:34

  本文选题：碳纳米管 + Fe-N/CNTs复合材料　； 参考：《西南交通大学》2017年硕士论文

【摘要】：具备优异的物理和化学性能碳纳米管(carbonnanotubes,CNTs)自1991年被发现以来。就被发掘出了诸多优点,例如,耐热性好,比表面积大,机械强度高等。碳纳米管通过与磁性粒子的有机整合(在碳纳米管表面包覆或管内填充磁性纳米粒子),可以同时综合两者的物理性质和化学性质,使其复合产物在催化剂、磁存储、生物医学、吸波剂等领域具有广阔的应用前景。因此,相较于其他材料,碳纳米管的复合材料的使用会使其具有出人意料的优异性能。本论文旨在采用填充法,在一定温度下制备出Fe-N/CNTs纳米复合材料,研究不同氨气流量对样品组织、成分与性能的影响,并分析其制备形成机理,为开发新型磁性碳纳米管的应用方面提供试验与理论基础。本论文在之前研究工作的基础上,以平均直径20～50纳米的碳纳米管(纯度90%)为原料,使用Fe(N03)3的过饱和溶液并利用碳纳米管的毛细作用制备了 Fe(N03)3-CNTs复合物。将该粉末经过干燥后,在650℃不同氨气流量(0.1～2m3/h)下进行气体氮化处理2h,并在无氨气氛围下进行对比实验,对其实验进行初步探究。同时对不同工艺制备的样品进行显微组织的观察及物相结构、磁学性能、吸波性能的测试与分析。研究结果表明,本论文利用填充法,通过碳纳米管的毛细作用与不同的氨气流量成功制备了具有填充型磁性碳纳米管复合材料,磁性粒子主要包括γ'-Fe4N、ε-Fe3N、ξ-Fe2N以及及-Fe22O。在Fe-N//NTs复合材料的制备过程中,因为不同氨气流量量获得不同氮含量的Fe-N合金。在650℃渗氮时,由于纳米Fe203颗粒的出现以及氮势与硝酸铁浓度控制得当,使反应偏离了理论上的共析转变。在本论文Fe-N/CNTs复合材料的制备工艺中,650℃保温2h且氨气流量0.5m3/h时所得到的γ'-Fe4N/CNTs具有较高的饱和磁化强度(91.79emu/g)、矫顽力(219.350e)、磁学性能分布均匀和低频段吸波性能潜力巨大(RL=-10.91dB)等最佳的综合性能。在对比试验中,无氨气的氛围下Fe(N03)3/CNTs中Fe(N03)3受热分解成α-Fe203后发生一系列转变并通过Fe3O4生成γ-Fe203。γ-Fe203/CNTs 不仅具有良好的磁学性能(Ms=61.86emu/g、Hc=232.50e)而且在吸波性能方面也因其阻抗匹配更优于Fe-N/CNTs复合材料也较为出众,故具有更好的吸波性能(d=1.8mm,RL=-34.23dB,有效带宽为1.2GHz)。Fe4N/CNTs复合材料的阻抗匹配还有所欠缺,故在吸波剂方面还需要进一步研究与拓宽。
[Abstract]:Carbon nanotubes with excellent physical and chemical properties have been discovered since 1991. Many advantages have been discovered, such as good heat resistance, large specific surface area, high mechanical strength and so on. Through organic integration with magnetic particles (coating or filling the carbon nanotubes with magnetic nanoparticles), carbon nanotubes can combine the physical and chemical properties of the two products in catalyst, magnetic storage, biomedicine. Wave absorbers and other fields have a broad application prospects. Therefore, compared with other materials, the use of carbon nanotubes composites will make it have unexpected excellent performance. In this paper, Fe-N/CNTs nanocomposites were prepared by filling method at a certain temperature. The effects of different ammonia flow rates on the microstructure, composition and properties of the samples were studied, and the mechanism of their preparation was analyzed. It provides experimental and theoretical basis for the development of new magnetic carbon nanotubes. On the basis of previous research work, the Fe(N03)3-CNTs composites were prepared by using the supersaturated solution of Fe(N03)3 and the capillary action of carbon nanotubes (CNTs) with an average diameter of 20 ~ 50 nanometers (purity 90 kum). After drying, the powder was nitrided for 2 h at 650 鈩，

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