超声辅助下液相共沉淀法制备掺镝铁氧体纳米晶

发布时间：2018-01-11 18:23

本文关键词：超声辅助下液相共沉淀法制备掺镝铁氧体纳米晶　出处：《安徽理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：纳米铁氧体磁颗粒是一类纳米功能材料。由于它的尺寸量级为纳米级,单磁畴宽度和超顺磁临界尺寸都小于100nm,颗粒中的原子数量大大减少,所以纳米磁性材料具有特殊的晶型结构和各种异常的磁现象,其电阻率、介电性能、光电性能也相对比较优异。通过对铁氧体进行稀土掺杂,如重稀土离子Dy3+、Er3+、Gd3+等,会使铁氧体产物的磁性能有显著的提高,进而满足在特种应用方面,如航空、冶炼、医学等特殊领域的应用要求。本文阐述了以 Fe2(SO4)3·xH2O、FeSO4·7H2O、Dy(NO3)3·xH20 为原料、以NH3·H20为沉淀剂,在超声辅助下采用液相共沉淀法制备出不同粒径的掺镝铁氧体磁性纳米晶,晶粒的粒径通过调节工艺参数(反应温度、搅拌转速、反应时间和超声强度)进行控制。用X射线荧光光谱仪(XRF)分析产物的化学成分、用X射线衍射仪(XRD)确定样品的相结构和平均粒径、用振动样品磁强计(VSM)测定纳米晶在室温下的磁性能。研究弱碱(NH3·H20)环境对掺镝铁氧体的生成、化学成分、粒径、形貌及磁性能的影响。正交实验结果分析表明反应温度、反应时间、搅拌转速对Dy3+的掺入量具有影响,且影响强度依次减弱;XRF分析表明:样品中的金属氧化物主要为Dy203、Fe203、MgO,且磁性相Dy203与Fe203的质量分数均达到80%以上;XRD分析表明:经过表面修饰的掺镝铁氧体纳米晶其晶型结构为反尖晶石型面心立方结构,结晶度较高。引入超声辅助手段后,磁晶粒的晶型结构不会发生改变,且仍具有较高的结晶度;VSM测试结果表明:纳米晶的磁性能与其粒径有关,饱和磁化强度(Ms)、矫顽力(Hc)和剩余磁化强度(Mr)随粒径的减小而降低,借助超声辅助制备纳米晶时,后期超声辅助会使纳米晶尺寸产生较小幅度的降低;全程超声辅助会引起纳米晶尺寸产生较大幅度的降低,最大降幅达35%。纳米晶尺寸的减小,会引起饱和磁化强度(Ms)、矫顽力(HC)和剩余磁化强度(Mr)的减小,磁滞现象减弱,超顺磁性增强。
[Abstract]:Nano ferrite magnetic particles is a kind of functional nano materials. Due to its nanometer size scale, single magnetic domain width and superparamagnetic critical size is less than 100nm, the number of atoms in the particles is greatly reduced, so the magnetic nano materials with special crystal structure and various abnormal magnetic phenomena, the resistivity, dielectric electrical properties, optical properties are relatively excellent. Through of rare earth doped ferrite, such as heavy rare earth ions Dy3+, Er3+, Gd3+ and so on, the magnetic ferrite products can improve significantly, and then meet in special applications, such as aerospace, metallurgy, medicine and other special application requirements in the field of this paper expounds on the Fe2 (SO4) 3 - xH2O, FeSO4, 7H2O, Dy (NO3) 3 - xH20 as raw materials, with NH3 H20 as precipitant, liquid phase were prepared by doped with Dysprosium Ferrite magnetic nanoparticles with different particle sizes used in ultrasonic assisted, grain size by adjusting Section parameters (reaction temperature, stirring speed, reaction time and ultrasonic intensity) control. Using X ray fluorescence spectrometer (XRF) analysis of the chemical composition of the product, by X ray diffraction (XRD) to determine the phase structure of samples and the average particle diameter by vibrating sample magnetometer (VSM) determination of magnetic nanocrystals at room temperature the research base. (NH3 - H20) generation environment of dysprosium doped ferrite chemical composition, particle size, morphology and magnetic properties. The orthogonal experiment results show that the reaction temperature, reaction time, stirring speed on the incorporation of Dy3+ has an impact, and the impact strength decreases; XRF analysis show that the metal oxides in the samples were mainly Dy203, Fe203, MgO, and the mass fraction of magnetic phase Dy203 and Fe203 reached 80% or more; XRD analysis showed that after doped with Dysprosium Ferrite Nanoparticles surface modified the crystal structure for inverse spinel type face centered cubic structure. The crystal degree is higher. By introducing auxiliary means, the crystalline structure of magnetic grains will not change, and still has a higher crystallinity; VSM test results show that the magnetic nanoparticles can be related to the particle size, saturation magnetization (Ms) and coercivity (Hc) and remanent magnetization (Mr) with the particle size decreases, with the aid of ultrasonic assisted preparation of nanocrystals, the late ultrasonic will make the nanocrystal size decrease with smaller amplitude; the whole ultrasonic can cause the nanocrystal size decrease greatly, reduce the maximum drop of 35%. nanocrystal size, will cause the saturation magnetization (Ms), the coercive force (HC) and remanent magnetization (Mr) decreases, the hysteresis phenomenon weakens, superparamagnetism is enhanced.

【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM277

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