尖晶石型Mn-Zn、Ni-Zn铁氧体磁性纳米晶的软化学可控制备及性能研究

发布时间：2018-01-19 00:34

本文关键词： 尖晶石结构纳米晶水热法微乳液法　出处：《四川师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文以硝酸盐和金属氯化物等为原料、Na OH为沉淀剂,在相对温和的条件下,通过水热法和微乳液法制备了尖晶石型Mn-Zn、Ni-Zn铁氧体系列磁性纳米晶。探究了水热法和微乳液法各自主要工艺参数(溶液p H值、表面活性剂与水的物质量之比ω、反应温度、反应时间、Na OH浓度、组分配比和稀土元素掺杂等)对制备Mn-Zn、Ni-Zn铁氧体纳米晶微结构和磁性能的影响。分别通过XRD、SEM和VSM等测试手段对所制备的纳米晶的微结构、形貌和磁性能进行了表征。研究结果如下:(1)水热法制备了Mn-Zn、Ni-Zn铁氧体系列磁性纳米晶,工艺参数对纳米晶的微结构和磁性能具有如下影响:a)溶液pH值对铁氧体纳米晶的微结构具有显著的影响。随着pH值增大,[OH-]相应增加,金属离子沉淀完全并生成对应化学计量比的尖晶石型纳米晶,样品晶化度得到改善。b)反应温度和反应时间对样品的纳米晶粒径有一定的影响,适当升高反应温度、延长反应时间有利于提高样品的晶化度。c)当x=0.5时获得的Mnx Zn1-x Fe2O4纳米晶具有最好的晶化度。Nix Zn1-x Fe2O4纳米晶的晶化度随着Ni含量的增大而改善。d)当Gd3+掺杂浓度较低时,Mn-Zn、Ni-Zn铁氧体纳米晶的晶格不会发生畸变;当掺杂浓度过高时,样品的晶格发生畸变,Gd3+无法完全进入晶格而产生杂相。e)当掺杂量y=0.02时,获得的铁氧体即MnFe1.98Gd0.02O4纳米晶比饱和磁化强度(σs)最大,为67.2 emu/g。(2)微乳液法制备了Mn-Zn、Ni-Zn铁氧体系列磁性纳米晶,工艺参数对纳米晶的微结构和磁性能具有如下影响:a)NaOH浓度对铁氧体纳米晶的微结构和晶化度具有重要的影响:在选定范围内,随着[OH-]浓度的增大,铁氧体纳米晶的粒径明显增大,样品晶化度也因此得到改善。b)表面活性剂与水的比值ω、反应温度和反应时间对铁氧体纳米晶的微结构影响甚微。c)在选定的工艺条件范围内,Mnx Zn1-x Fe2O4和Nix Zn1-x Fe2O4纳米晶的晶化度随着二价离子(Mn2+、Zn2+或Ni2+)含量比例的变大而变差;所制备的Ni-Zn铁氧体纳米晶中Ni0.7Zn0.3Fe2O4纳米晶比饱和磁化强度(σs)最大,为41.11 emu/g。。d)Ho3+的掺杂不会对Mn-Zn、Ni-Zn铁氧体纳米晶的粒径产生明显的影响。但是当掺杂浓度过高时,样品发生晶格畸变,Ho3+离子无法进入晶格而产生杂相。
[Abstract]:In this paper, spinel Mn-Zn was prepared by hydrothermal method and microemulsion method with nitrate and metal chloride as raw materials, NaOH as precipitant, under relatively mild conditions. Ni-Zn ferrite series magnetic nanocrystals. The main technological parameters of hydrothermal method and microemulsion method (pH value of solution, mass ratio of surfactant to water), reaction temperature and reaction time were investigated. The effects of NaOH concentration, composition ratio and rare earth element doping on the microstructure and magnetic properties of nanocrystalline Mn-ZnN Ni-Zn ferrite were investigated by XRD. The microstructure, morphology and magnetic properties of the prepared nanocrystals were characterized by SEM and VSM. The results are as follows: 1) Mn-Zn was prepared by hydrothermal method. Ni-Zn ferrite series magnetic nanocrystals. The process parameters have the following effects on the microstructure and magnetic properties of nanocrystals: a) the pH value of the solution has a significant effect on the microstructure of ferrite nanocrystals. [With the increase of OH-, the metal ions precipitate completely and form spinel nanocrystals corresponding to stoichiometric ratio. The crystallization degree of the sample was improved. The reaction temperature and reaction time had a certain effect on the particle size of the nanocrystalline, and the reaction temperature was raised appropriately. Prolonging the reaction time can improve the crystallinity of the sample. The Mnx Zn1-x Fe2O4 nanocrystals obtained when x = 0.5 have the best crystallinity. Nix Zn1-x. The crystallinity of Fe2O4 nanocrystals improved with the increase of Ni content. D). When the doping concentration of Gd3 is low. The lattice of Mn-ZnN Ni-Zn ferrite nanocrystals will not be distorted. When the doping concentration is too high, the lattice distortion Gd3 of the sample can not enter the lattice completely and the heterogenous phase. E) when the doping amount is Y0. 02. The maximum saturation magnetization (蟽 s) of MnFe1.98Gd0.02O4 nanocrystalline was obtained, which was 67.2 emu / g 路g. 2) microemulsion method to prepare Mn-Zn. Ni-Zn ferrite series magnetic nanocrystals. The process parameters have the following effects on the microstructure and magnetic properties of nanocrystalline: the concentration of NaOH has an important effect on the microstructure and crystallinity of ferrite nanocrystalline: within the selected range, with. [With the increase of the concentration of OH-, the particle size of ferrite nanocrystalline increases obviously, and the crystallinity of the sample also improves the ratio 蠅 of surfactant to water. The reaction temperature and reaction time have little effect on the microstructure of ferrite nanocrystals. The crystallization degree of Mnx Zn1-x Fe2O4 and Nix Zn1-x Fe2O4 nanocrystalline is with the divalent ion MNO _ 2. The ratio of Zn2 or Ni2) increased and became worse. The specific saturation magnetization (蟽 s) of Ni0.7Zn0.3Fe2O4 nanocrystals is the highest in the prepared Ni-Zn ferrite nanocrystals. The doping of 41.11 emu/g..d)Ho3 has no obvious effect on the particle size of Mn-ZnPn-Ni-Zn ferrite nanocrystals, but when the doping concentration is too high. The crystal lattice aberration of the sample can not enter the crystal lattice and the heterogenous phase is produced.
【学位授予单位】：四川师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

【参考文献】