【作者】 谷红微；

【导师】 安茂忠；

【作者基本信息】 哈尔滨工业大学 ， 化学工程与技术， 2010， 硕士

【摘要】 多孔阳极氧化铝（PAA）膜具有独特的、均匀的纳米级柱状孔阵列结构,以其为模板,在离子液体中采用电沉积方法制备磁性金属纳米线阵列,可得到具有优良的垂直磁各向异性和超高密度的磁记录介质,这对开发新型高密度存储材料具有重要意义。本文以0.3mol·L^-1草酸溶液为电解液,采用两次阳极氧化（一次阳极氧化1h,二次阳极氧化2h）制备多孔阳极氧化铝模板。氧化结束时,阶梯降压处理,以降低阻挡层厚度。之后,将多孔阳极氧化铝模板放入2g·L^-1氯化铁的饱和草酸水溶液扩孔液中扩孔处理5.5h。以该方法得到的多孔阳极氧化铝为阴极,在离子液体[BMIM]BF₄电解液中电沉积制备了Sm-Co合金纳米线阵列膜和Tb-Fe-Co合金纳米线阵列膜。电沉积得到的Sm-Co合金纳米线阵列膜中的纳米线中钐含量较高,其质量分数达到90%,纳米线的长度约为2μm,纳米线直径与多孔氧化铝模板的孔径相一致,约为70nm。XRD分析表明,Sm-Co合金纳米线的组成主要为SmCo5和Sm₂Co₁₇。通过正交试验确定了较优的脉冲电沉积Tb-Fe-Co合金的电解液组成为:Fe（BF₄）₂ 0.75mol·L^-1,Co（BF4）2 0.75mol·L^-1,Tb（BF4）3 1.5mol·L^-1,1,4-丁炔二醇2g·L^-1。在该镀液中进行电沉积,可以获得Tb含量最高为31mass%的Tb-Fe-Co三元合金。离子液体中制备的Tb-Fe-Co合金纳米线粗细均匀,纳米线直径与多孔氧化铝模板的孔径相一致,均为70nm左右。不同的电沉积时间,可得到不同纳米线长度（0.5².5μm）的Tb-Fe-Co合金纳米线阵列膜。XRD分析表明,Tb-Fe-Co合金纳米线组成主要为Tb₂Co₁₇和FeCo。磁性能测试结果表明,组装在多孔阳极氧化铝中的Sm-Co合金纳米线阵列膜具有明显的垂直磁各向异性,矩形比为0.30,矫顽力为314Oe。对组装在多孔阳极氧化铝中的Tb-Fe-Co合金纳米线阵列膜的测试表明,Tb含量低于20mass%时,Tb-Fe-Co合金纳米线阵列膜没有明显的垂直磁各向异性;当Tb含量大于20mass%时开始具有明显的垂直磁各向异性,随着Tb含量的增加,矫顽力（Hc）和剩余磁化强度（Mr）逐渐增大。针对Tb质量分数为31%的Tb-Fe-Co合金纳米线,研究了电沉积时间对Tb-Fe-Co合金纳米线阵列膜的磁性能的影响,结果表明,电沉积时间低于15min时,Tb-Fe-Co合金纳米线阵列膜没有明显的垂直磁各向异性;电沉积时间高于15min时,Tb-Fe-Co合金纳米线阵列膜有明显的垂直磁各向异性,随着沉积时间的延长,矫顽力（Hc）和剩余磁化强度（Mr）逐渐增大。电沉积时间为20min时纳米线阵列膜的垂直磁性能最好,Tb-Fe-Co合金纳米线阵列膜的矩形比为0.41,矫顽力为574Oe。更多还原

【Abstract】 Porous anodic alumina （PAA） membrane has a unique uniform nano-columnar pore array structure, it can be used as the template when electrodeposite the magnetic metal nanowires in ionic liquid. The obtained magnetic metal nanowire is a kind of ultra-high density magnetic recording media with good perpendicular magnetic anisotropy. This has great importance for developing new high-density magnetic storage materials.In this paper, porous anodic alumina template was prepared in the electrolyte of 0.3 mol·L^-1 oxalic acid with using two anodic oxidation （one hour the first time, then two hour continuously）. Then potential was steped down to make the barrier layer thinner. The anodic oxidation of porous anodic alumina template was puted in 2g·L^-1 ferric chloride solution saturated oxalic acid solution 5.5 hours. Then the Sm-Co alloy nanowire array film and Tb-Fe-Co alloy nanowire arrays film was prepared using the anodic oxidation of porous anodic alumina as cathode, ionic liquid [BMIM] BF4 as electrolyte.The nanowires in Sm-Co alloy nanowire array film have a high content of samarium, which can reach 90% by weight. The nanowire has a length about 2μm, 70nm in diameter, which was consistent with pore size of the porous anodic alumina template, there are two main crystal structure in Sm-Co alloy nanowire array film, SmCo₅ and Sm₂Co₁₇.To obtain a high content of Tb in Tb-Fe-Co nanowire, the composition of electrolyte was determined by orthogonal experiments, the result is: the concentration of Fe（BF4）2 is 0.75 mol·L^-1, the concentration of Co（BF₄）₂ is 0.75 mol·L^-1, the concentration of Tb（BF4）3 is 1.5 mol·L^-1, the concentration of 1,4 - butynediol is 2g·L^-1, in this condition, the content of Tb in Tb-Fe-Co nanowire can reach 31% in weight. The diameter of Tb-Fe-Co nanowire was about 70nm, which was consistent with the pore size of porous anodic alumina template, the length of the Tb-Fe-Co nanowire was from 0.5μm to 2.5μm, crystal structure of Tb-Fe-Co nanowire are Tb₂Co₁₇ and FeCo.Magnetic testing of Sm-Co alloy nanowire array film shows that it has obvious perpendicular magnetic anisotropy. Squareness ratio was 0.30, the coercivity was 314Oe. Magnetic testing of Tb-Fe-Co with different Tb content show that perpendicular magnetic anisotropy is not significant when the content of Tb is less than 20 mass %, with the increase of Tb content, both the the coercivity （Hc） and remanent magnetization （Mr） increase, Tb-Fe-Co show obvious perpendicular magnetic anisotropy when the content of Tb greater than 20 mass %.Then the Tb content is fixed at 31 mass%, magnetic testing of Tb-Fe-Co alloy nanowire array film with different deposition time was performed. The result show that perpendicular magnetic anisotropy is not obvious when the deposition time less than 15min, with the increase of deposition time, both the coercivity （Hc） and remanent magnetization （Mr） increased, Tb-Fe-Co show obvious vertical magnetic anisotropy when the deposition time greater than 15min. Tb content is 31 mass%, deposition time is 20min, the rectangular ratio was 0.41, the coercivity was 574Oe.更多还原