【作者】 王永飞；

【导师】 李巧玲；

【作者基本信息】 中北大学 ， 材料学， 2008， 硕士

【摘要】 本文介绍了永磁铁氧体磁性材料以及SrFe₁₂O₁₉纳米粒子的发展历史和典型的制备方法。确定生成粒径较小且分散均匀的硬磁铁氧体纳米粒子时,Fe3+与络合剂的最佳摩尔比和pH,水用量等各因素。在此基础上利用联合络合法和加入无机盐制备出形貌可控的纳米SrFe₁₂O₁₉,并分析其形成机理,优化工艺提高各种形貌SrFe₁₂O₁₉磁性能。对SrFe₁₂O₁₉掺杂,并与α-Fe2O3或γ-Fe2O3的交换耦合,研究掺杂和交换耦合对SrFe₁₂O₁₉磁性的影响。（1）采用柠檬酸法制备SrFe₁₂O₁₉纳米粒子,考虑用水量,PH值,柠檬酸:金属离子摩尔比,煅烧温度,煅烧时间对柠檬酸法制备SrFe₁₂O₁₉的影响,得出柠檬酸法制备纯的粒径较小且分散均匀的纳米SrFe₁₂O₁₉的最佳工艺为柠檬酸与金属离子的摩尔比为1:1,pH值为6,用水量为120 ml,并且在900℃下煅烧2 h。（2）在最佳制备工艺的基础上,采用联合络合法以草酸、硬脂酸和EDTA为辅助络合剂与柠檬酸进行联合络合制备出球形、纺锤体、棒状、针状的纳米SrFe₁₂O₁₉,并得出纺锤体、棒状、针状SrFe₁₂O₁₉的最佳制备工艺,重点研究辅助络合剂对SrFe₁₂O₁₉的形貌、粒径、分散性以及磁性能的影响,结果表明:针状SrFe₁₂O₁₉的矫顽力最大,其次为棒状,纺锤体,球形的最小。（3）在柠檬酸法制备纳米SrFe₁₂O₁₉的基础上,在煅烧过程中加入KCl、KBr和KI等无机盐制备出针状、棒状和空心球的纳米SrFe₁₂O₁₉,并控制KCl、KBr和KI的用量得出最佳制备条件。重点研究了在制备过程中无机盐对SrFe₁₂O₁₉的形貌、粒径、分散性以及磁性能的影响。（4）在EDTA-柠檬酸联合络合法制备SrFe₁₂O₁₉的基础上进行掺杂,研究掺杂物质对SrFe₁₂O₁₉磁学性能的影响,最终制得了矫顽力为6052.5 Oe,饱和磁化强度和剩余磁化强度分别为71.8 emu·g-1和42.5 emu·g-1的M型锶铁氧体,保证了矫顽力和磁化强度的同高。（5）对SrFe₁₂O₁₉与α-Fe2O3或γ-Fe2O3进行复合,研究复合后M铁氧体磁性能的变化规律,通过控制煅烧温度,最终制得了矫顽力为6198.3 Oe,比饱和磁化强度和比剩余磁化强度分别为71.5 emu·g-1和42.3 emu·g-1的γ-Fe2O3/ SrFe₁₂O₁₉复合Sr-M型铁氧体,使样品的综合磁性能得到进一步的提高。更多还原

【Abstract】 In the paper, the development history and typical preparation method of permanent magnetic ferrite material were introduced. The factors （optimistic mol ratio of Fe3+ to precursor, pH, water volume and so on） to obtain fine and dispersing homogeneously permanent magnetic ferrite particles were determined. At the base of craft, co-completion method and inorganic salt were used to prepare controllable morphology nano-SrFe₁₂O₁₉.The mechanism was analyzed. The craft was optimized to improve the magnetic properties of various morphologies.SrFe₁₂O₁₉ was doped, cross coupled withα-Fe2O3 orγ-Fe2O3.The influence of doping and cross coupling to magnetic properties were studied.（1）The water volume, pH value, the mol ratio of citric acid to metal ion, calcination temperature was determined to prepare pure fine well-dispersed nano-SrFe₁₂O₁₉ with citric acid method. The optimum craft was as follow: the molar ratio of citric acid to metal ion was 1:1,the pH value was 6,the volume of water was 120 ml, calcinated 900℃at 2 h.（2）As the optimum preparation craft, ethanedioic acid、stearic acid and EDTA were used as co-complex agent to obtain spherical、spindle、rod-like、needle-like nano-SrFe₁₂O₁₉ respectively. The influence of co-complex agent to the morphology, diameter, dispersion character, magnetic properties of SrFe₁₂O₁₉ was studied. The result indicated that the coercivity of needle-like samples was maximum, the coercivity of rod-like samples spindle samples spherical samples decreased gradually.（3）At the base of preparation of nano- SrFe₁₂O₁₉, KCl、KBr and KI were added in the calcination process to prepare needle-like、rod-like and bubble nano-SrFe₁₂O₁₉ respectively. The optimum quantity of KCl、KBr and KI was determined. The influence of inorganic salt to the morphology, diameter, dispersion character, magnetic properties of SrFe₁₂O₁₉ was studied.（4）The SrFe₁₂O₁₉ were doped at the base of EDTA-citric acid co-complex method. The influence of the doped agent to the magnetic properties of SrFe₁₂O₁₉ was studied. The coercivity, saturation magnetization and remanent magnetization of prepared samples were 6052.5 Oe,71.8 emu·g-1and 42.5 emu·g-1 respectively.（5）α-Fe2O3 orγ-Fe2O3 was recombined with SrFe₁₂O₁₉,the change mechanism of M-ferrite was analyzed. The coercivity, saturation magnetization and remanent magnetizationγ-Fe2O3/ SrFe₁₂O₁₉ Sr-M style ferrite composite were6198.3 Oe,71.5 emu·g-1 and 42.3 emu·g-1 respectively. The comprehensive magnetic properties of samples was improved.更多还原