Co—Sn替代钡铁氧体的制备及其磁性

用化学共沉淀工艺制备了可望用作高密度垂直磁记录介质的Ｃｏ－Ｓｎ替代钡铁氧体系列微粉样品ＢａＦｅ１２－２ｘＣｏｘＳｎｘＯ１９，其中ｘ可取值为０，０．２，０．４，０．５，０．６，０．８，１．２，给出了最佳制备条件：反应温度ｔ＝８０℃，体系的ｐＨ值ｐＨ＝１１．８，热处理温度Ｔｈ＝９２５℃，对所制备的系列样品进行了透射电镜观测和Ｘ光衍射测试，给出了颗粒的形貌和大小以及晶体结构和晶格常数。用振动样品磁强计对     

Li-Zn-Cu和Li-Zn-Co系铁氧体Mossbauer效应研究

在室温条件下,测量了多晶铁氧体（Ｌｉ０．５Ｆｅ０．５）０．７－ｘＺｎ０．３ＣｕｘＦｅ２Ｏ４（ｘ＝０．０;０．０３;０．０５;０．０７）和（Ｌｉ０．５Ｆｅ０．５）０．７ｙ＝Ｚｎ０．３ＣｏｙＦｅ２Ｏ４（ｙ＝０．０;０．０１;０．０２;０．０３）的Ｍｏｓｓｂａｕｅｒ谱,结果表明,离子代换使样品的Ｍｏｓｓｂａｕｅｒ谱变得复杂。所有谱线均包含一组强度很弱的顺磁双线亚谱。     

Y（Fe1—xCox）11.3Nb0.7化合物的结构与磁性研究

粉末样品的Ｘ射线衍射和热磁曲线测量表明,所有Ｙ（Ｆｅ１－ｘＣｏｘ）１１．３Ｎｂ０．７（ｘ＝０,０．０５,０．１０,０．２０）化合物具有ＴｈＭｎ１２型结构,且有良好的单相性Ｃｏ替代Ｆｅ引起居里温度Ｔｃ显著提高和晶格常数的单调减小,室温下的饱和磁化强度Ｍｓ随Ｃｏ含量的增加在ｘ＝０．１～０．２之间呈现极大值,各向异性场Ｂａ随ｘ的增加,先增加而后减小     

n－GaAsTi／Mo／Ti／Au中肖特基势垒接触稳定性的研究

对Ｔｉ／Ｍｏ／Ｔｉ／Ａｕ作为栅金属的ＧａＡｓＭＥＳＦＥＴ进行了高温反偏（ＨＴＲＢ）、高压反偏（ＨＲＢ）、高温正向大电流（ＨＦＧＣ）、高温存贮（ＨＴＳ）４种不同的应力试验。通过ＨＲＢ，φｂ从０．６４ｅＶ减少到０．６２ｅＶ，理想因子ｎ略有增大，ＨＴＳ试验中φｂ从０．６７ｅＶ增加到０．６９ｅＶ。分析表明，这归因于界面氧化层的消失，以及Ｔｉ与ＧａＡｓ的反应；ＨＦＧＣ试验结果表明，其主要的失效模式为烧毁，同时，ＳＥＭ观察中也有电徙动及断栅现象发生。ＡＥＳ分析表明，应力试验后的样品，其肖特基势垒接触界面出现模糊，有明显的互扩散和反应发生。     

n－GaAsTi／Mo／Ti／Au中肖特基势垒接触稳定性的研究

对Ｔｉ／Ｍｏ／Ｔｉ／Ａｕ作为栅金属的ＧａＡｓＭＥＳＦＥＴ进行了高温反偏（ＨＴＲＢ）、高压反偏（ＨＲＢ）、高温正向大电流（ＨＦＧＣ）、高温存贮（ＨＴＳ）４种不同的应力试验。通过ＨＲＢ，φｂ从０．６４ｅＶ减少到０．６２ｅＶ，理想因子ｎ略有增大，ＨＴＳ试验中φｂ从０．６７ｅＶ增加到０．６９ｅＶ。分析表明，这归因于界面氧化层的消失，以及Ｔｉ与ＧａＡｓ的反应；ＨＦＧＣ试验结果表明，其主要的失效模式为烧毁，同时，ＳＥＭ观察中也有电徙动及断栅现象发生。ＡＥＳ分析表明，应力试验后的样品，其肖特基势垒接触界面出现模糊，有明显的互扩散和反应发生。     

对PrFe_10.2Mo_1.5Co_0.3结构的中子衍射研究

为研究ＰｒＦｅ１０．２Ｍｏ１．５ＣＯ０．３永磁合金样品中Ｃｏ的加入对磁性能的影响,采用粉末中子衍射研究方法确定了它的晶体结构与磁结构．Ｒｅｉｔｖｅｌｄ峰形精修法对中子衍射数据的拟合得到了Ｍｏ择优占据８ｉ替代晶位、Ｃｏ择优进入８ｊ替代晶位的的结果．Ｃｏ替代８ｊ晶位部分Ｆｅ导致磁矩和和磁化强度增强,居里温度升高．     

铋钙铟钒石榴石单晶磁晶各向异性的研究

通过对｛Ｂｉ０．４Ｃａ０．６｝［Ｆｅ２－ｙＩｎｙ］（Ｆｅ１．７Ｖ１．３）Ｏ１２（ｕ＜０．３）的室温穆斯堡尔谱分析确定非磁性离子Ｉｎ３＋进入八面体（ａ）晶位置换部分Ｆｅ３＋．按单离子模型对ＢｉＣａｌｎＶＩＧ单晶温磁晶各向异性常数与掺铟量的关系进行叠代得出Ｆｅ３＋离子在单晶ＢｉＣａＶＩＧ和ＢｉＣａＩｎＶＩＧ四面体和八面体晶位上对磁晶各向异性有大体相同的贡献．     

鄂东南晚二叠世大隆组层状硅质岩成因地球化学及沉积环境

鄂东南地区的晚第二叠世大隆组中存在数层与地层融合产生的薄层状硅质岩，其微量元素，微量元素，稀土元素，硅和氧同位素地球化学特征表明其为热水沉积硅基岩，Ａｌ－Ｆｅ－Ｍｎ和Ｆｅ－Ｍｎ－（Ｎｉ＋Ｃｏ＋Ｃｕ）三角图上，硅质岩属较典型的热水沉积硅质岩，硅质岩ＭｎＯ／ＴｉＯ２〈０．５，δＣｅ平均值为０．８０，δ＾３０Ｓｉ值为０．３×１０＾－３～０．７×１０＾－３，表明本区晚二叠世大隆组层状硅质岩主要在浅海环境下     

BaCO3基熔剂对高炉锰铁预脱硅处理的实验研究

实验室内,用ＢａＣＯ３基熔剂对硅含量为０．８％～１．７％的高炉锰铁进行预脱硅处理,处理温度１３００～１４００℃,实验结果表明,对于初始硅含量（Ｓｉ）〉１．０％和（Ｓｉ）≤１．０％的两种类型高炉锰铁,前者需要通过二次预脱硅处理,后者只需实施一次脱硅预处理,脱硅后的两类合金均能满足后步氧化脱磷关于硅含量限制范围的要求,通过实验确定了脱硅剂的优化组成是ＢａＣＯ３（８０％）－ＢａＦ２（１０％）－ＭｎＣＯ３     

纤维C—内标技术对TN12M10合金的SHS反应过程

利用特殊的Ｃ－内标技术对ＴＮ１２Ｍ１０合金的ＳＨＳ反应结晶过程进行了实验研究，发现包裹Ｃ－粒的包覆熔体中含有杂质与合金元素，随着温度升高，Ｃａ，Ｓｉ，Ｆｅ，Ｎｉ的含量减少，直至消失，Ｔｉ，Ｍｏ含量则随之增加；ＢＦＴ最后流到就近的Ｔｉ（Ｍｏ）Ｃ晶粒上结晶。因之，作者提出了ＴＮ１２Ｍ１０合金ＳＨＳ反应结晶过程的顺序：（１）Ｃａ，Ｓｉ，Ｎｉ，Ｆｅ，Ｔｉ，Ｍｏ等杂质及合金元素随着加热温度铁升高，依次先后熔     

Rheological properties of magnetorheological fluid prepared by gelatin-carbonyl iron composite particles

Gelatin — carbonyl iron composite particle was prepared by micro emulsion method. The analysis of scanning electron microscope(SEM) shows that the ultrafine particles are spheroids coated by gelatin, and the average sizes of particles are 3 – 10 μm. The specific saturation magnetization σ_s is 130.9 A · m²/kg, coercivity H _c is 0.823 A/m, and residual magnetism r is 4.98 Am²/kg for the composite particles. It is shown that the particles possess properties of soft magnetic. The yield stress of magnetorheological fluid (MRF) with composite particle reaches 70 kPa at 0.5 T magnetic induction. Magnetorheological effects are superior in lower magnetic field intensity and the subsidence stability of the MRF is excellent compared with pure carbonyl iron powder.     

Preparation and Characterization of Monodisperse Nickel Nanoparticles by Polyol Process

Polymer-protected monodisperse nickel nanoparticles were synthesized by a modified polyol reduction method in the presence of poly（N-vinyl-2-Pyrrolidone）.These nanoparticles were characterized by transmission electron microscopy（TEM）,X-ray diffraction（XRD）,selected area electron diffraction（SAED）,as well as vibrating sample magnetometer（VSM）.The experimental results show that the addition of PVP and the concentration of NaOh have strong influences on the size.agglomeration and uniformity of nanoparticles.In the presence of PVP and NaoH with low concentration.smonodisperse nickel nanoparticles with average diameters about 42 nm were obtained and characterized to the pure nickel crystalline with foc structure.Secondary structures such as clusters.loops.and strings resulted from magnetic interactions between particles were observed.The chemical interaction between the PVP and nickel nanoparticles was found by FTIR.The saturation magnetization（Ms）.remanent magnetization（Mr）and coercivity（Hc）of these nickel nanoparticles are lower than those of bulk nickel.     

硬软磁纳米复合薄膜的制备及其磁性能

为制备电磁性能优异的薄膜,运用溶胶-凝胶浸渍提拉法制备出BaFe12O19/Ni0.8Zn0.2Fe2O4复合膜,借助X射线衍射仪(XRD)、扫描电子显微镜(SEM)、振动样品磁强计(VSM)和矢量网络分析仪等分析手段表征了复合膜的结构、形貌、并对样品的磁性能和吸波性能进行了研究。结果表明,制得的复合膜在950℃下磁滞曲线呈单一相,磁性能最好,其剩磁高于硬软单膜,饱和磁化强度(Ms)、剩余磁化强度(Mr)和矫顽力(Hc)分别达到32.45emu/g、11.22emu/g和1203.24G。复合薄膜与硬软单膜相比,也有利于拓宽吸收频带,改善其吸波性能。     

Powder Extrusion Molding of Nanocrystalline WC-10Co Composite Cemented Carbide

The rods that were shaped from nanocrystalline WC- 10.21 Co-0.42 VC/ Cr3 C2 （ wt% ） composite powders by using powder extrusion molding （PEM） were investigated. The nanocrystalline WC- 10.21 Co- 0. 42 VC/ Cr3 C2 （ wt% ） composite powders were prepared by the spray thermal decomposition-continuous reduction and carburization technology. In order to improve the properties of rods shaped by using powder extrusion molding, the cold isostatic pressing （CIP） technology was used before or after debinding. Specimens were siutered by vacuum siutering and hot isostatic pressing （HIP）. The density, Rockwell A hardness, magnetic coercivity , and magnetic saturation induction of siutered specimen were measured. The microstructure of the green bodies and the siutered specimens was studied by scanning electron microscopy （SEM）. Results show that the rod formed by using powder extrusion molding after debinding and followed by cold isostatic pressing can be siutered to 99.5% density of composite cemented carbide rods with an average grain size of about 200- 300 nm, magnetic coercivity of 30.4 KA / m, Rockwell A hardness of 92.6 and magnetic saturation induction of 85% . Superfine WC- 10 Co cemented carbide rods with excellent properties were obtained.     

Fe_xPt_(100-x)薄膜的磁性能研究

用直流磁控溅射方法和原位退火工艺在玻璃基片上制备了FexPt100-x纳米膜.研究发现Fe含量对FePt纳米膜的磁特性有很大的影响.矫顽力和△H随Fe含量的增加而增大.当x=48时,矫顽力Hc达到了1040 kA/m,样品出现很好的有序化L10织构;△H取得最大值,颗粒间相互作用最小.FexPt1-x薄膜的矩形比S随着x的增加而增大,x>46时S值接近1,在一定程度上表明了此时读出信号强度较大;开关场分布SFD的变化情况刚好与此相反,Fe48Pt52获得的SFD值近似等于0.8,说明转变位置波动弱,来自转变的信号噪音低.     

Fe3O4磁流体的水热法制备与表征

采用水热法制备了水基Fe3O4磁流体,利用X衍射仪(XRD)和透射电镜(TEM)对磁粒子的组成、结构及粒径进行了分析,利用古埃磁天平研究了磁流体的饱和磁化强度和稳定性,证实所制得的磁粒子为纯相Fe3O4纳米粒子,平均粒径为9nm左右,磁流体饱和磁化强度为46mT,稳定性较好。     

纳米级固溶体Ce0.8Y0.2O1.9的反相微乳法控制合成

尺寸可控、高分散和超细的纳米级固溶体的制备是获取高性能固体氧化物燃料电池的重要环节之一.采用水/CTAB/环己烷/中等碳链长度醇组成的反相微乳体系制备出了粒径分布均匀、平均晶粒尺寸为5.0～8.0 nm的Ce0.8Y0.2O1.9超细粉体，考察并初步讨论了反相微乳体系中几种因素对最终产物的尺寸和形貌的影响，包括助表面活性剂、不同水与表面活性剂摩尔比、反应物浓度、陈化时间、碱液浓度等.所得产物用TEM进行分析，结果表明,助表面活性剂、不同水与表面活性剂摩尔比及陈化时间对产物影响不大，但反应物浓度及碱液浓度对产物的晶粒粒径大小有一定的影响.     

Effects of Heat Treatment Temperature and Time on Structure and Static Magnetic Property of W-type Ferrite Hollow Microspheres

Hollow spheres of hexagonal ferrite BaCo2Fe16O27 were fabricated through a spray pyrolysis technique using co-precipitation ferrite powder precursor as materials, followed by calcinations in an air atmosphere. The phase composition, micro-morphology, and static magnetic property of the particles were measured by XRD, SEM, and VSM. The results indicate that the method for preparation of ferrite hollow microspheres (FHM) results in a broad particles size distribution. The density of FHM decreased from 5.31 g/ cm3 to 2.31 g/cm3. When the heating rate was 5 ℃/min, and temperature was 1 200 ℃ for 4 hours, pure W-type ferrites were formed. With the heat treatment temperature and time increasing, the crystal structure becomes perfect, the saturation magnetization is increased and the coercive force is decreased.     

纳米ZnFe_2O_4的柠檬酸盐前驱体法制备与表征

采用柠檬酸盐前驱体法制备纳米ZnFe2O4颗粒,并通过TG-DTA、XRD、TEM和磁性能测试对纳米Zn-Fe2O4颗粒进行表征。结果表明,柠檬酸盐前驱体在500℃×2 h煅烧后可得到单一ZnFe2O4相。通过XRD分析,纳米ZnFe2O4晶粒粒径为21 nm,与TEM分析结果一致;在300 K下测得纳米ZnFe2O4饱和磁化强度为3.5 emu/g,剩磁为0.61 emu/g,矫顽力为17.508 kA/m。