本文關鍵詞： 尖晶石結構 納米晶 水熱法 微乳液法　出處：《四川師范大學》2015年碩士論文　論文類型：學位論文

【摘要】：本文以硝酸鹽和金屬氯化物等為原料、Na OH為沉淀劑,在相對溫和的條件下,通過水熱法和微乳液法制備了尖晶石型Mn-Zn、Ni-Zn鐵氧體系列磁性納米晶。探究了水熱法和微乳液法各自主要工藝參數(shù)(溶液p H值、表面活性劑與水的物質(zhì)量之比ω、反應溫度、反應時間、Na OH濃度、組分配比和稀土元素摻雜等)對制備Mn-Zn、Ni-Zn鐵氧體納米晶微結構和磁性能的影響。分別通過XRD、SEM和VSM等測試手段對所制備的納米晶的微結構、形貌和磁性能進行了表征。研究結果如下:(1)水熱法制備了Mn-Zn、Ni-Zn鐵氧體系列磁性納米晶,工藝參數(shù)對納米晶的微結構和磁性能具有如下影響:a)溶液pH值對鐵氧體納米晶的微結構具有顯著的影響。隨著pH值增大,[OH-]相應增加,金屬離子沉淀完全并生成對應化學計量比的尖晶石型納米晶,樣品晶化度得到改善。b)反應溫度和反應時間對樣品的納米晶粒徑有一定的影響,適當升高反應溫度、延長反應時間有利于提高樣品的晶化度。c)當x=0.5時獲得的Mnx Zn1-x Fe2O4納米晶具有最好的晶化度。Nix Zn1-x Fe2O4納米晶的晶化度隨著Ni含量的增大而改善。d)當Gd3+摻雜濃度較低時,Mn-Zn、Ni-Zn鐵氧體納米晶的晶格不會發(fā)生畸變;當摻雜濃度過高時,樣品的晶格發(fā)生畸變,Gd3+無法完全進入晶格而產(chǎn)生雜相。e)當摻雜量y=0.02時,獲得的鐵氧體即MnFe1.98Gd0.02O4納米晶比飽和磁化強度(σs)最大,為67.2 emu/g。(2)微乳液法制備了Mn-Zn、Ni-Zn鐵氧體系列磁性納米晶,工藝參數(shù)對納米晶的微結構和磁性能具有如下影響:a)NaOH濃度對鐵氧體納米晶的微結構和晶化度具有重要的影響:在選定范圍內(nèi),隨著[OH-]濃度的增大,鐵氧體納米晶的粒徑明顯增大,樣品晶化度也因此得到改善。b)表面活性劑與水的比值ω、反應溫度和反應時間對鐵氧體納米晶的微結構影響甚微。c)在選定的工藝條件范圍內(nèi),Mnx Zn1-x Fe2O4和Nix Zn1-x Fe2O4納米晶的晶化度隨著二價離子(Mn2+、Zn2+或Ni2+)含量比例的變大而變差;所制備的Ni-Zn鐵氧體納米晶中Ni0.7Zn0.3Fe2O4納米晶比飽和磁化強度(σs)最大,為41.11 emu/g。。d)Ho3+的摻雜不會對Mn-Zn、Ni-Zn鐵氧體納米晶的粒徑產(chǎn)生明顯的影響。但是當摻雜濃度過高時,樣品發(fā)生晶格畸變,Ho3+離子無法進入晶格而產(chǎn)生雜相。
[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.
【學位授予單位】：四川師范大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1

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