锰锌铁氧体中的锌测定

锰锌铁氧体在工业上有广泛的用途,但其中的锌含量测定一直没有很满意的分析方法。常用的萃取法手续繁琐,且回收率偏低,重现性较差。本文研究了锰锌铁氧体中锌的直接容量滴定方法,在pH1～2条件下,加过硫酸铵煮沸使Mn~(2+)转化成二氧化锰沉淀分离,过滤。滤液以氟化物掩蔽铁,在pH=5.4或pH=5.5条件下,以二甲酚橙(XO)为指示剂,EDTA直接滴定至终点,所拟方法准确度高,重现性好,结果满意。     

铁氧体吸波材料

一、引言吸波材料有多种用途,隐身飞行器就是用吸波材料构成或涂敷,再加上进行特殊的形状设计等形成的飞行器,将使现有微波雷达、红外雷达或其它电磁波雷达以及声波探测系统都几乎不可能发现它。目前电视已广泛进入千家万户,而在城     

替代M-型钡铁氧体纳米粒子的微波吸收性能

The microwave-absorbing behavior of substituted M-type barium ferrite nano-particles was investigated. The nano-particles were synthesized with coprecipitation-melted salt method. For the purpose of comparison, corre-sponding micro-particles were also prepared through direct coprecipitation and sintering. XRD and TEM of the nano-particles showed that the ferrite was hexagonal in structure and widely distributed in size with particle size being less than 100nm, the complex permittivity and permeability of a 1.50mm thick specimen and a 1.40mm thick specimen containing 60% by weight of substituted M-type barium ferrite nano-particles and micro-particles were measured respectively in X band (8.2～12.4GHz) range, from which the reflection loss (R.L.) of microwaves was calculated and two comparative absorption curves were given. The results showed that the synthetic nano-particles could well absorb microwaves in X band. The absorption was larger than 10dB in the range of 9.2～12.4GHz while the maximum absorption was 38.6dB at 10.6GHz.     

水热法制备超顺磁性铁氧体纳米微粒

本文通过水热法制备了一系列铁氧体纳米微粒(MFe₂O₄,M=Zn,Ni,Co,Cu,Mn),用XRD和TEM对产品进行了表征,产物为纯相、粒径均匀、团聚少的纳米粒子。磁性质测量表明它们具有超顺磁性质。另外,我们还对反应过程中溶液pH值对最终产物的影响进行了研究。     

镝铁氧体／聚丙烯酰胺磁性复合微球的制备及其表征

微舍微乳液聚合和纳米反应器两种技术。在W／O微乳液体系中制备出镝铁氧体／聚丙烯酰胺磁性复合微球。通过IR，XRD，TEM，TG等分析测试手段对产物结构、粒径、形貌等进行了表征。同时对复合微球的磁响应性进行了初步研究。结果表明：所制得的磁性复合微球具有良好的磁响应性和悬浮稳定性。     

层状前体镍铁水滑石及磁性材料的制备及表征

提出了利用镍铁水滑石作为磁性前体再经高温焙制备尖晶石型铁氧体思路，深 入研究了水滑石的制备工艺及结构性能并初步探讨了其焙烧后的磁学性能。由共沉 淀法合成了Ni/Fe摩尔比为2，3，4，6的镍铁水滑石，XRD结果表明镍铁比为3时晶 形较为理想，且随着晶化温度的升高及晶化时间的延长，水滑石的晶体结构规整性 增强。热重-差热结果显示镍铁水滑石的分解有两个过程，当镍铁比为3时，水滑石 的热稳定性相对最高。高温焙烧后的镍铁水滑石具有磁性。     

稀土Z型铁氧体Ba3-xCexCo2Fe24O41的制备及其微波吸收性能

采用溶胶-凝胶法合成了掺杂Ce的磁铅石型系列Z型钡铁氧体(Ba3-xCexCo2Fe24O41,x=0.00～0.40).结果表明,Z型钡铁氧体的最佳成相条件为1250 ℃/5 h;测试不同烧结温度下Ba3Co2Fe24O41的吸波特性,发现经1300 ℃/5 h烧结后所得试样对微波的吸收特性最为优良,最大衰减量可达35.012 dB.经1300 ℃/5 h下得到的Ba3-xCexCo2Fe24O41(x=0.00～0.40)的吸波特性分析表明,适量掺杂Ce可以提高Z型钡铁氧体的吸波特性,当x=0.3时有最大衰减量47.575 dB.     

甚高频用超低饱和磁化强度In∶BiCaVIG晶体生长及磁特性研究

利用加速坩埚转动技术制备了超低饱和磁化强度(M_s)石榴石型In∶BiCaVIG单晶铁氧体材料,系统研究了单晶样品的晶体结构、微观形貌及磁学性能。结果表明:In∶BiCaVIG单晶样品结晶良好,具有体心立方结构;样品的居里温度为104 ℃,饱和磁化强度为60 G,饱和磁化强度偏差达到±20 G, 略优于美国Microphere公司同类型材料产品。经过抛光处理后的球形样品线宽明显减小,最小线宽为5.8 Oe,这是因为化学抛光处理可以均匀腐蚀加工应力层,导致线宽减小。另外,与未掺杂BiCaVIG单晶相比,超低饱和磁化强度样品的线宽明显要大,这主要跟样品的饱和磁化强度大小有关。     

Doping effects on structural and magnetic evolutions of orthoferrite SmFe（1-x） Alx O3

The structural and magnetic properties of SmFeO3 with B site substitution of non-magnetic atom A1 are investigated. The x-ray diffraction patterns show that SmFe（1-x）AlxO3 remains an orthorhombic structure within the whole doping range, and the unit-cell volume decreases monotonically with the increase of doped A1 concentration. Besides, the octa- hedral tilting distortions of FeO6 are found to be alleviated while the tolerance factor increases. However, the relationship between the lattice parameters and Al concentration is observed to deviate from Vegard＇s rule, and this may be caused by magnetostriction effects. For the doping content values in a range 0 〈 x 〈 0.6, the ferromagnetism, antiferromagnetism, and paramagnetism are observed to occur continuously. Moreover, the magnetization and the spin reorientation temperature （Tk） decrease monotonically as Al content value increases. With the doping content values being x = 0.8 and 1.0, these compounds only show paramagnetic behavior.