【作者】 陈学刚；

【导师】 宋怀河； 张兴英；

【作者基本信息】 北京化工大学 ， 材料学， 2001， 硕士

【摘要】 作为纳米材料的一种，纳米金属粒子／炭材料是一种新型的功能性复合材料，可望在电子、电工、电波屏蔽、氧化／还原催化剂、抗菌剂、特种活性炭制备等方面获得广泛应用。针对目前研究中系统性差，制备工艺复杂，炭中金属含量难以调节等缺点，本课题分别以模型芳烃和精制石油渣油为炭源，以二茂铁为金属源，采用热缩聚—溶剂抽提—炭化工艺合成纳米铁粒子均匀分散于炭基体中的特殊材料，探讨工艺参数对产物形态和性能的影响，用SEM、TEM、XRD、HRTEM、XPS、VSM等现代分析手段对材料的结构、性能进行深入分析，提出纳米铁粒子分散于炭基体中所致材料的结构模型，并对纳米铁／炭材料的形成机理进行初步探讨。 二茂铁单独炭化虽然可以得到纳米铁／炭复合材料，但由于体系中铁含量过高，炭基体不能形成连续相，使Fe与空气中的氧气迅速反应而得不到纳米单质铁粒子，而得到铁的氧化物粒子。 二茂铁与萘在420℃不同停留时间的共炭化可以得到比较单一的纳米α-Fe／炭材料，其中铁粒子的直径在20～60nm左右，均匀分散于炭基体中。 在二茂铁与石油渣油体系的共炭化过程中，二茂铁的存在可以显著提高石油渣油的热缩聚速率，提高缩聚转化率，产物中吡啶不溶组分（PI）较石油渣油单独缩聚有明显增加。二茂铁的催化作用使石油渣油很容易形成融并体型的中间相。 初始缩聚产物中，粒径在20～50nm范围内的铁粒子均匀分布于炭基体中。铁的微晶排列有序，并诱导炭层有序排列，沉积在铁粒子表面形成特殊的包覆结构，在铁粒子与炭层的界面处，炭层表现出较高的有序性。而承载这种粒子的绝大多数炭是无定型的乱层结构。由于渣油中除主要含有C、H元素外，尚含有N、S及O等异原子，因此，由此前驱体制备的初始产物结构和组成相对复杂，在主要含α-Fe的同时，体系中还含有一定数量的铁的氧化物（主要是Fe₃O₄）和铁的硫化物（Fel.xS）。经700一900’C高温热处理后，低温炭化产物中的Fe3O;和Fe，_xs数量减少，向生成。一Fe和奥氏体铁方向转化。 磁性能测试表明，该材料的饱和磁化值均较大，剩磁较小，表现出典型的软磁性质。可望在信息记录材料等方面获得应用。关键词:二茂铁，石油渣油，纳米铁粒子，炭，磁性能更多还原

【Abstract】 Nano-metal/carbon composite is a new functional material, which can be widely used as electronic, electric, electromagnetic shield materials, oxidation/reduction catalysts, antibacterial materials and special active carbon etc. Presently, most researches focused on the synthesis of nano-metal/carbon from organometallic polymers and macromolecular-metal complexes , which led to some problems, such as complicated process and difficulty of metal content control. In this thesis, a model aromatic hydrocarbon, e.g., naphthalene and a petroleum refined residue were used as the raw carbon sources and ferrocene as metal source to synthesize the special nano-iron/carbon material through condensation-solvent extraction-carbonization processes. The effects of preparation parameters on the pyridine insoluble fractions and morphologies of nano-iron/carbon were studied and the structural features and magnetic property were investigated by SEM, TEM, XRD, HRTEM, XPS, VSM etc. The formation mechanism and model of nano-iron/carbon were also discussed.Although nano-iron/carbon composite can be obtained from the direct carbonization of ferrocene at 420℃, it can not exist in air and easily react with oxygen due to the unstability of the naked nano-iron particles in air. From the co-carbonization of ferrocene and naphthalene the nano-iron/carbon material was prepared, in which the diameter of the iron particle dispersed in carbon matrix uniformly is about 20~60nm.The addition of ferrocene accelerated the reaction velocity of petroleum residue condensation and increased the pyridine insoluble fraction yield obviously. In the resulting material, the diameter of the iron particle is about 20~50nm. The ultra-fine iron crystal arranges orderly and induce the carbon to encapsulate the nano-iron particle. The matrix carbon is amorphous.Because of the existence of the heteroatoms such as O, S, N etc. in petroleum residue, the nano-composite contains not only the main a -Fe particles but also some amount of Fe3O4and Fe,.xS compounds. After further heat treatment at 700-900 ℃ for 1 hour, the Fe3O4and Fe1-xS disappeared gradually and transformed into a -Fe and austenitic iron.The result of the magnetism test indicated that the nano-iron particle/carbon material have the typical soft magnetism and can be magnetized/demagnetized repeatedly, which may be as the candidate of information record materials.更多还原