Mgx／Mg2Ni复合储氢合金的机械合金化制备及电极性能

利用Mg2Ni合金和不同质量百分数的Mg粉(x=10％，30％，50％)混合后球磨制得Mgx／Mg2Ni复合合金。XRD分析证实，Mg2Ni合金和Mg粉混合球磨时无新相生成，Mg粉的添加可有效抑制Mg2Ni合金单独球磨时存在的Mg2Ni相的分解反应。采用模拟电池法测试了Mgx／Mg2Ni复合合金的电极性能，结果表明，Mg量的增加可显著地提高复合合金的放电容量。在球磨的开始阶段，复合合金的放电容量随球磨时间的延长而增加，球磨一定时间后，其放电容量则随球磨时间的延长而迅速降低。放电容量与球磨时间的变化关系体现了球磨对复合合金微结构改变的影响。     

热处理对TbFeCr合金微波吸收性能的影响

采用电弧熔炼与高能球磨相结合的方法制备Tb9Fe88Cr3合金粉体,利用XRD、SEM和矢量网络分析仪分析粉体的微结构及微波吸收性能。研究发现进行微氧化处理的合金微粉在低频端吸波性能优于未处理的合金微粉。在微氧化处理基础上,进一步研究热处理温度对合金微波吸收性能影响,研究发现:当热处理温度在350℃时,吸收峰在7GHz处,其峰值达到–11.5dB,随着真空热处理温度升高,合金微粉吸收峰向低频移动,反射率增大;当热处理温度为450和550℃时,吸收峰频率与仅做微氧化处理合金的吸收频率相近,吸收峰值减小了2~3dB,低频端吸波性能得到进一步改善。     

壳聚糖复合膜的制备及其界面的生物功能化

采用电沉积方法在电极上沉积了壳聚糖-琼脂糖复合膜,考察了复合膜的组成对生物分子特异性吸附的影响.采用电化学方法对生物复合膜进行了活化,并共价组装了免疫生物分子,构建了免疫分析体系,通过电场的作用排除了非特异性吸附.研究结果表明,在电场的作用下,所沉积的生物复合膜有效地排除了生物分子非特异性吸附,提高了免疫检测的准确性.     

机械球磨对烧结形成Mg2Ni相的影响

本文分析了球磨处理对烧结时Mg2Ni相形成的影响。试验结果表明，球磨处理后的Mg、Ni混合粉晶粒细化，并形成了有利于原子扩散的微结构(如界面密度、晶格缺陷密度增加等)，从而使烧结时MgaNi相更易形成。X衍射和DSC分析也证实，烧结形成Mg2Ni相的过程中无中间相的产生，适当的球磨处理会影响Mg2Ni相形成的温度和焓变(△H)，可使Mg2Ni相形成在较低温度范围(770K左右)下进行。     

AN INVESTIGATION OF THE PERMANENT MAGNETS Nd_(15)(Fe, Co)_(77)B_8 WITH Dy AND Al ADDITIVES

Nd-(Fe,Co)-B alloys with Dy and Dy-Al additives have been studied by the Mossbauer effect and X- ray diffraction. The results indicate that the alloys consist of a tetragonal phase, a B-rich phase and a Nd-rich phase. The average magnetic moment of Fe atoms in the tetragonal phase has been determined. The variation of remanence due to Dy and Dy- Al additives has been derived from the Mossbauer data and found to agree with the results of magnetic measurements. The site substitutions of Dy and Al in the alloys are also discussed.     

Cu-Fe-Sn三元系合金相图

为探讨 Fe 元素在锡青铜中的机理行为,本工作是在 Cu-Fe,Cu-Sn 和 Fe-Sn 三个二元系相图基础上,用 X 射线粉末衍射法、金相法和微差热分析法测定了 Cu-Fe-Sn 三元系合金相图的室温截面和600℃等温截面.配制合金所用的材料是纯度为99.99%的Fe 和99.99%的电解 Cu 以及光谱纯的 Sn.每个试样按3g 配料,用感量为0.1mg 的光电天平测量,配料盛于 Al_2O_3坩埚内,在稍大于1个大气压的氩气保护下的高频感应炉中熔炼.熔好后的合金样品呈钮扣状,表面光滑,失重率小于     

Microwave absorbing properties of NdFeCo magnetic powder

NdFeCo magnetic powder was prepared by the process of smelting,high-energy ball milling and oxidation heat treating.The effects of oxidation heat treatment and Co content on phase composition and microwave absorbing properties of NdFeCo magnetic powder were investigated by an X-ray diffractometer(XRD)and vector network analyzer.The minimum reflectivity of Nd23.25Fe36.75Co40 powder before oxidation heat treatment was-6.2 dB,and that of oxidized powder decreased to-14.0 dB.The microwave absorbing properties of NdFeCo magnetic powder could be improved effectively by oxidation heat treatment.With the increase of Co content,the Fe2O3 reduced and the Nd2O3 increased;Fe3Co7 phase appeared when the content of Co increased to 40%(mass ratio);the absorption peak was found to move towards lower frequency region first,and then it moved towards a higher frequency region.Nd23.25Fe66.75Co10 powder had better comprehensive properties in absorbing microwave in the frequency band of 3-13 GHz.The value of minimum reflectivity and absorption peak frequency,when the coating thickness(d)was 1.8 mm,were-19.7 dB and 4.8 GHz,respectively.     

Crystal structure and magnetic behavior of the La0.1Bi0.9FeO3 compound

The nano-crystalline La_(0.1)Bi_(0.9)FeO_3 compound was successfully synthesized by starch-based combustion method. The crystal structure and magnetic behavior were studied by temperature-dependent X-ray diffraction(XRD), scanning electron microscopy(SEM), differential scanning calorimetry(DSC) and magnetic measurements. The La_(0.1)Bi_(0.9)FeO_3 compounds crystallized in a rhombohedrally distorted perovskite structure with space group R3 c. The substitution of La for Bi reduced the rhombohedral distortion. The structural phase transitions in La_(0.1)Bi_(0.9)FeO_3 driven by temperature showed that the extraordinary two-phase coexistence state of BiF eO 3 and LaF eO 3 was observed in a narrow temperature range of 630–700 oC. The magnetization of the La_(0.1)Bi_(0.9)FeO_3 sample was improved by heat treatment in the temperature range. When the heat treatment temperatures rose from 25 to 600 oC, the remanence(Mr) and coercivity(Hc) of the La_(0.1)Bi_(0.9)FeO_3 compound almost remained the same, and increased rapidly to 0.134 emu/g and 7.1 KOe on further increasing the heat treatment temperature to 650 oC.     

Phase Transformation and Magnetic Properties of NdxFe60.5-xPt39.5 （x=0, 0.5, 1.0, 1.5） Alloys

The effect of Nd addition on the structure, phase transformation and magnetic properties of FePt based alloys was investigated. The results indicated that the transition temperature from ordered FCT to disordered FCC phase decreased with increasing Nd concentration, but for alloys quenched rapidly from the γ phase region into ice-water, it increased with increasing Nd. The Nd element not only effectively reduced the grain size of the ordered phase but also decreased the degree of the ordered phase and refined the grains of the FCC matrix phase. The remanence ratio and coereivity of the FePt based alloy as a function of the Nd content had maximum values, respectively.     

机械合金化La8Mg52Ni40合金的相组成研究

采用机械合金化及热处理等方法制备了．La8Mg52Ni40新型合金，并用X-射线衍射(XRD)、扫描电子显微镜(SEM)、差热分析(DTA)等方法研究了其组织结构及热稳定性能等．研究结果表明：La8Mg52Ni40合金经280r／min球磨250h后．获得了镧、镁、镍等非晶相和MgNi2纳米晶结构；所得粉末的形状为规则的球形或近球形，颗粒直径范围约为0．05～12．5μm，其中，粒径为0．5～2μm的颗粒数约占颗粒总数的97％．球磨样品经763K保温35d热处理后，得到了具有纳米尺度的Mg2NiLa，Mg2Ni，MgNi2三相合金，样品具有较好的热稳定性能．图4，表2，参12．