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水热法合成无稀土永磁材料的研究

时间:2019-06-01 20:06来源:毕业论文
柠檬酸钠和氢氧化钠是合成钴的过程中很重要的两个影响因素,柠檬酸钠的浓度影响钴合成的内部生长结构,而氢氧化钠充当还原剂,将溶液中的钴离子还原成钴

摘要  磁性材料曾在人类文明史上具有重要的地位,促进了世界文化的交流和传播。现代社会磁性材料更是广泛应用于信息储存、电机、医疗、磁分离等众多的领域。 本文研究的是不含稀土元素的ConC 磁性材料体系,因为六方紧密堆积的Co 具有很强的硬磁性,以及非常大的各向异性。整个的实验过程可以分为三个部分来阐述,首先,实验研究了水热法合成纳米级的钴的工艺条件。实验得出合成纳米钴的各原料的最适比,再通过控制加热时间和温度来比较不同温度、时间下,溶剂热反应的不同所合成的纳米钴的性能的不同;其次,将纳米级的钴和碳纳米管真空封装后,放在电阻炉或者马弗炉里进行热处理,研究 ConC 纳米颗粒的合成与磁性能的变化;最后,将碳纳米管直接掺杂到钴的水热合成过程中, 研究添加量对合成过程和产物结构的影响。研究结果表明柠檬酸钠和氢氧化钠是合成钴的过程中很重要的两个影响因素,柠檬酸钠的浓度影响钴合成的内部生长结构,而氢氧化钠充当还原剂,将溶液中的钴离子还原成钴。经过热处理的纳米钴和碳纳米管合成了ConC 粉体,此方法合成的 ConC 相是 Co、Co2C、Co3C、CoC8 的混合相,并且热处理温度的不同,合成样品的磁性能也不同。在水热法合成钴的过程中直接添加碳纳米管合成的ConC 粉体,相比未添加碳纳米管的样品,矫顽力和饱和磁化强度都变大了。   35881
毕业论文关键词:水热合成法;纳米级钴;碳纳米管;热处理;ConC 粉体 
Abstract  Magnetic material plays an important role in  the history of human civilization, which greatly promotes the communication and communication of world culture. Nowdays,the magnetic material is widely used in the field of information storage, motor, medical, magnetic separation etc. The paper is a study of ConC magnetic material system, which is not containing rare earth elements. Because Cobalt of hexagonal closed-packed has strong hard magnetic properties, and very large anisotropy. The whole process can be pided into three parts. Firstly, The experiment studies the technological conditions for nanometer cobalt by hydrothermal synthesis method. The results show that the optimum ratio of reaction raw materials, then controlling the heating time and temperature to compare the different properties of cob alt nanoparticles in different solvent thermal reaction. Secondly, after the nano cobalt and carbon nanotubes were vacuum packed, they were heat treated in the resistance furnace. This is mainly to study the synthesis and magnetic properties of ConC nanoparticles. Finally, in the experiment, the carbon nanotube is directly doped into the hydrothermal synthesis process of cobalt to study the amount of influence on the synthesis process and the resulting product structure. The results show that Sodium citrate and sodium hydroxide are two very important factors in the process of synthesis of cobalt. The concentration of sodium citrate affects the internal growth structure of cobalt synthesis. While sodium hydroxide acts as reducing agent, cobalt ions can be red uced to cobalt. ConC powders that were synthesized by heat treatment process of cobalt and carbon nanotubes. The ConC phase synthesized by this method is the mixed phase of Co, Co2C, Co3C and CoC8. And with the difference of heat treatment temperature, the magnetic properties of the sample are also different. Synthesis of ConC powders by direct addition of carbon nanotubes during hydrothermal synthesis process of cobalt. Compared with the sample without CNTs, the coercivity and saturation magnetization of the samples have been become larger. 
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Key Words:hydrothermal  synthesis;  nanometer cobalt;  carbon nanotubes; heat treatment; ConC powder  
目录
1绪论.1
1.1引言.1
1.2磁性材料.1
1.2.1硬磁材料1 水热法合成无稀土永磁材料的研究:http://www.lwfree.cn/cailiao/20190601/34060.html
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