磁性铁粉毕业设计 - 图文

江汉大学

JIANGHAN UNIVERSITY

本科生毕业论文（设计） 题 目 草酸盐体系制备超细铁粉的实验研究 学生姓名 指导老师

学 院 机电与建筑工程学院 专业班级

完成时间 2013年6月 1

摘要 ..................................................................... 4 ABSTRACT ............................................................... 5 第一章 文献综述 .......................................................... 6

1.1超细粉体材料的性能 ................................................ 6

1.1.1量子尺寸效应 ................................................. 6 1.1.2小尺寸效应 ................................................... 6 1.1.3表面效应 ..................................................... 7 1.1.4宏观量子隧道效应 ............................................. 7 1.2超细粉体的制备方法 ................................................ 7

1.2.1化学法 ....................................................... 7 1.2.2物理法 ....................................................... 9 1.3超细铁粉的应用 ................................................... 11

1.3.1冶金工程生产中应用 .......................................... 11 1.3.磁性材料工业中的应用 ......................................... 12 1.3．3粉末冶金中应用 ............................................. 13 1.3.4焊条制造业中应用 ............................................ 13 1.3.5医学生物工程中的应用 ........................................ 14 1.3.6 电子工程中的应用 ........................................... 14 1.4超细粉体材料的制备方法 ........................................... 14

1.4.1液相法 ...................................................... 14 1.4.2气相法 ...................................................... 15 1.4.3固相法 ...................................................... 16 1.5本课题意义和内容 ................................................. 17

1.5.1本课题研究的意义 ............................................ 17 1.5.2本课题研究的内容 ............................................ 18

第二章 液相沉淀法制备超细铁粉的机理研究 ................................. 19

2.1前言 ............................................................. 19 2.2 Fe(Ⅱ)-NH3-SO42--C2O42--H2O体系热力学平衡分析 ...................... 19

2.2.1 H2C2O4—H2O平衡体系的热力学分析 ........................... 19 2.2.2 体系Fe(II)-NH3-SO42--C2O42--H2O计算基本思路及过程 ............ 21 2.3 体系Fe(Ⅱ)-NH3-SO42--C2O42--H2O热力学计算结果及分析 ............... 22

2.4.1超细铁粉成核过程 ............................................ 25 2.4.2超细铁粉的形貌和粒度控制 .................................... 26 2.4.3超细铁粉制备过程中的防团聚机理及方法 ........................ 26 2.5 本章小结 ......................................................... 26 第三章 草酸盐体系制备超细铁粉的实验研究 ................................. 28

3.1引言 ............................................................. 28 3.2实验仪器及药品 ................................................... 28 3.3实验流程 ......................................................... 29 3.4实验装置 ......................................................... 29 3.5分析检测 ......................................................... 30 3.6实验条件对FeC2O4粉体形貌和粒度的影响 ............................ 30

3.6.1离子浓度对FeC2O4粉体形貌和粒度的影响 ....................... 30 3.6.2 pH值对超细铁粉形貌和粒度的影响研究 ......................... 31

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3.6.3反应时间的影响 .............................................. 33 3.6.4反应温度的影响 .............................................. 34 3.6.5加料方式的影响 .............................................. 35 3.6.5陈化时间的影响 .............................................. 36 3.6.6沉淀剂对超细形粒度和形貌的影响 .............................. 36 3.7最优实验条件确定 ................................................. 36

3.7.1沉淀物的形貌与粒度控制 ...................................... 37 3.7.2沉淀物粉末结晶性状分析 ...................................... 38 3.8超细铁粉的X射线衍射分析 ......................................... 39 3.9本章小结 ......................................................... 40 第四章 结论和建议 ....................................................... 41

4.1草酸盐体系制备超细铁粉的结论 ..................................... 41 4.2草酸盐体系制备超细铁粉的建议 ..................................... 41 参考文献 ................................................................ 43 致 谢 ................................................................... 45

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摘要

超细铁粉具有电、磁、光等性质, 不仅影响材料的烧结性能, 而且关系到材料最终物理性能，在电磁屏蔽、材粉末冶金料等领域，得到广泛的应用，它是现代材料科学开发新研究领域之一；可应用在磁性钥匙，高密度金属型磁带，票证，电磁波吸收材料，也可作为成核中心生长碳纤维，广泛用于粉末冶金、减摩材料、润滑剂等制品，在电磁学、医学、冶金等领域有广阔前景[1]。

本文研究了以液相沉淀法制备超细铁粉，通过体系各因素的分析，确定出了制备超细铁粉合适工艺条件，从溶液化学性质的角度，探讨了沉淀粉末粒度和结构形貌的变化的规律。使得沉淀反应完全，混合均匀，形貌为类球形多面体、粒度分布窄的超细铁粉。

在绘制出沉淀过程热力学化学位图的基础之上，结合反应沉淀，结晶动力学等方面的原理和思路对实验结果进行综合分析，研究表明：各实验因素如反应温度、反应物浓度、加料的方式、陈化的时间、添加剂等，对粉末的粒度、形貌的影响不同之处。控制添加剂的用量、低反应物的浓度、并加方式加料、较短的陈化时间，更利于获得粒度分布较窄，粒径较小的粒子。

当pH值在2～3范围内，加料浓度为0.6mol/L，采用反向加料，温度为400℃，加料时间为20min时，制备出的结晶形态良好，表面光滑枝晶少，呈短棒状，得到晶粒之间团聚轻的草酸亚铁粉末。

关键词：超细铁粉；化学共沉淀；草酸；粒度

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ABSTRACT

The ultrafine iron powder having electrical, magnetic, optical and other properties, not only affects the sintering properties of the material, but also to the final physical properties of the material, widely used in the field of electromagnetic shielding, powder metallurgy materials, such as wood, it is the development of modern materials science new areas of research; magnetic keys can be applied to high-density metal tape, the ticket, the electromagnetic wave absorbing material can also be used as a nucleation center-grown carbon fiber is widely used in powder metallurgy, antifriction materials, lubricants and other products, the electromagnetic, medicine, metallurgy and other fields and has good prospects [1].

This paper studies the liquid phase of ultra-fine iron powder prepared by precipitation through the investigation of the factors of the system to determine the appropriate process conditions for the preparation of samarium iron precursor powder, from the point of view of the chemical properties of the solution of the precipitate particle size and structural shape the variation of the appearance. Make the precipitation reaction completely, mixed evenly, morphology of spherical polyhedron, narrow particle size distribution of ultrafine iron powder.

Draw on the basis of thermodynamic chemical precipitation process bitmap binding

reaction precipitate, the principles and ideas of the crystallization kinetics and other aspects of a comprehensive analysis of the experimental results, studies show that: the experimental factors such as reaction temperature, concentration of reactants, feeding the, aging time, additives, the powder particle size, morphology. Low concentration of reactants, control the amount of additives, and add the feeding, the shorter the aging time is more conducive to obtain smaller particle size, narrower particle size distribution of particles; additives on the morphology of the particles have a good role .

When the pH value of 2 to 3, the feed concentration for the 0.6 mol / L, a temperature of 400 ° C, using the reverse feeding, the feeding time for 20min, when preparing a crystalline form good, smooth surface dendrite was short rod-shaped reunion light between the grains of ferrous oxalate powder was obtained.

Key words: ultra-fine iron powder;chemical precipitation; oxalic acid; particle size，

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