Fe—Ni／Cu磁性多层膜中层间耦合和磁性的研究

利用振动样品磁强计和电子顺磁共振谱仪研究了Ｆｅ－Ｎｉ／Ｃｕ多层膜中的层间耦合和二维效应，以及它们对磁性的影响，对于Ｆｅ－Ｎｉ（３．０ｎｍ）／Ｃｕ多层膜，面内饱和场Ｈｓ，矫顽力Ｈｃ，剩磁比均随Ｃｕ层厚度作同步振荡变化，对于Ｆｅ－Ｎｉ（２．０ｎｍ）／Ｃｕ和Ｆｅ－Ｎｉ（３．０ｎｍ）／Ｃｕ多层膜，有效饱和磁化强度与共振线宽ΔＨ，随Ｃｕ层厚度作同步振荡变化。在它们的铁磁共振谱中，除了一致进动共振模外，还存在     

Eu_（1－x）Sr_xFeO_（3－y）的~（57）Fe Mossbauer谱

报导Ｅｕ＿（１－ｘ）Ｓｒ＿ｘＦｅＯ＿（３－ｙ）（ｘ＝０．０～１．０）的固相反应法合成，测量了其Ｘ射线衍射及室温下的￣５７ＦｅＭｏｓｓｂａｕｅｒ谱。实验结果表明，Ｓｒ掺入了ＥｕＦｅＯ＿３晶格，结构变化与掺杂量密切相关。室温下￣５７ＦｅＭｏｓｓｂａｕｅｒ谱由一套反铁磁六线谱、一套顺磁双线谱和一套顺磁单线谱组成（Ｘ＝０．２，０．４，０．６）．处于立方相的Ｆｅ离子的ＩＳ介于Ｆｅ￣３＋和Ｆｅ￣４＋之间，可能参与电子跳跃。     

Li－Zn－Zr－Ti－Cu系铁氧体Mo．．ssbauer效应研究

在室温条件下测量了多晶铁氧体（Ｌｉ０．５Ｆｅ０．５）０．７Ｚｎ０．３（Ｚｒ１－ｙＴｉｙＣｕ）ｘＦｅ２－２ｘＢｉ０．００３Ｏ４（其中ｘ＝０．１，０．２，ｙ＝０．５，１．０）的Ｍｏ．．ｓｂａｕｅｒ谱．结果表明，样品谱包含一套顺磁双线亚谱，强度较弱（小于５％）．顺磁谱的出现是渗入了较多非磁性离子Ｚｎ，Ｔｉ和Ｚｒ引起的     

Li—Zn—Ti—Cu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）０．７Ｚｎ０．３（Ｚｒ１－ｙＴｉｙＣｕ）ｘＦｅ２－２ｘＢｉ０．００３Ｏ４（其中ｘ＝０．１，０．２，ｙ＝０．５，１．０）的Ｍｏｓｓｂａｕｅｒ谱。结果表明，样品谱包含一套顺磁双线亚谱，强度较弱，顺磁谱的出现是渗入较多非磁性离子Ｚｎ，Ｔｉ和Ｚｒ引起的。     

电沉积Ni－Fe合金的穆斯堡尔效应

对电沉积Ｎｉ－Ｆｅ合金的穆斯堡尔谱分析表明γ相Ｎｉ－Ｆｅ合金的同质异能移（Ｉ．Ｓ．）为－０．０６～０．０２ｍｍ／ｓ；α相的Ｉ．Ｓ为～＋０．０５ｍｍ／ｓ，与冶炼Ｎｉ－Ｆｅ合金的Ｉ．Ｓ．（冶炼Ｎｉ－Ｆｅ合金的γ相Ｉ．Ｓ为－０．１９～－０．２２ｍｍ／ｓ；α相Ｉ．Ｓ．为－０．０７～０．１０ｍｍ／ｓ）相比，向正值方向偏移，γ相平均偏移０．１８ｍｍ／ｓ，α相约０．１３ｍｍ／ｓ．电沉积Ｎｉ－Ｆｅ合金的磁超精细场随合金中Ｆｅ含量的变化情况与冶炼Ｎｉ－Ｆｅ合金中的情况不完全一样。此外，还观察到电四极裂矩不等于零，表明电沉积Ｎｉ－Ｆｅ合金中存在电场梯度．根据镀层合有杂质Ｓ和结构缺陷的特点，讨论了上述穆斯堡尔参数的变化情况。     

一维奇异非稳态问题全离散解的误差估计

研究如下奇异非稳态问题｛ｕｔ（ｘ，ｔ）－ｐ＾－１（ｘ）（ｐ（ｘ）ｕ＇（ｘ，ｔ））＇＋ｑ（ｘ）ｕ（ｘ，ｔ）＝Ｈ（ｘ，ｔ）ｔ〉０ ｘ∈Ｉ≡（０，１） ｕ＇（０，ｔ）＝ｕ（１，ｔ）＝０ ｔ〉０ ｕ（ｘ，０）＝ψ（ｘ）的有限元方法。分别使用Ｅｕｌｅｒ－Ｇａｌｅｒｋｉｎ方法和Ｃｒａｎｋ－Ｎｉｃｏｌｓｏｎ－Ｇａｌｅｒｋｉｎ方法，给出全离散解的加权Ｌ２模误差估计。     

氰基桥联铬（Ⅲ）—镍（Ⅱ）和铬（Ⅲ）—铜（Ⅱ）多核配合物的？…

合成了配合物「ＭＬ」３「Ｃｒ（ＣＮ）６」２．ｘＨ２Ｏ（Ｍ＝Ｎｉ,Ｌ＝三（２－胺基乙基）胺（ｔｒｅｎ）,ｘ＝０;Ｍ＝Ｃｕ,Ｌ＝ｆｇ ｇｍｗ ｏｑｄ ｄｇ ｅｐｖ （ｄｐｔ）ｘ＝８）和「Ｍ（ｔｎ）２」２「Ｃｒ（ＣＮ）６」ＣｌＯ４．ＸＨ２Ｏ（ｔｎ＝１,３－丙二胺,Ｍ－Ｎｉ,ｘ＝０;Ｍ＝Ｃｕ,ｘ＝２）。用元素分析、ＩＣＰ分析、ＩＲ光谱等对配合物进行了表征,测定了它们的磁性质,变产化率研究表明：「Ｃｕ（ｄｐ     

Ti－Code12合金焊后退火对组织性能的影响

研究了Ｔｉ－Ｃｏｄｅ１２合金（Ｔｉ－０．３Ｍｏ－０．８Ｎｉ）焊后退火对组织和性能的影响．结果表明焊后退火将引起残存β相的共析分解，共析分解产物Ｔｉ２Ｎｉ相具有面心立方结构．合金的耐蚀性来源于α基体上Ｔｉ２Ｎｉ相的存在，Ｔｉ２Ｎｉ相既可在晶间沉淀，也能在晶内沉淀．本研究对Ｔｉ－Ｃｏｄｅ１２合金耐蚀性机理提出了直接证据．     

低饱和场巨磁电阻金属多层膜Ni80Fe20／Cu的结构与磁电阻

采用磁控溅射方法，获得了具有低饱和场巨磁电阻的Ｎｉ８０Ｆｅ２０／Ｃｕ金属多层膜，在室温下，其磁电阻和层间耦合状态随Ｃｕ层厚度的增加呈振荡变化，在Ｃｕ层厚度ｔＣｕ＝１．０ｎｍ，２．２ｎｍ时磁电阻出现２个峰值分别为１９．４％和１１．７％，饱和场约为６．４×１０＾４Ａ／ｍ和８×１０＾３Ａ／ｍ低温下（７７Ｋ）磁电阻为３３．２％和２７．６％，系统地研究了ＮｉＦｅ层厚度和周期数对多层膜磁电阻的影响，用真空退火     

电沉积Ni—Fe合金的穆斯堡尔效应

对电沉积Ｎｉ－Ｆｅ合金的穆斯堡尔谱分析表明γ相Ｎｉ－Ｆｅ合金的同质异能移（Ｉ．Ｓ．）为－０．０６－０．０２ｍｍ／ｓ；ａ相的Ｉ．Ｓ．为－＋０．０５ｍｍ／ｓ，与冶冻Ｎｉ－Ｆｅ合金的Ｉ．Ｓ．（冶冻Ｎｉ－Ｆｅ合金的γ相Ｉ．Ｓ．为－０．１９－－０．０２ｍｍ／ｓ；ａ相Ｉ．Ｓ．Ｓ为－０．０７－０．１０ｍｍ／ｓ）相比，向正值方向偏移，γ相平均偏移０．１８ｍｍ／ｓ，ａ相约０．１３ｍｍ／ｓ，电沉积Ｎｉ－Ｆｅ合金的磁超     

Santa Catharina and the origin of cloudy taenite in meteorites

CLOUDY taenite appears as a dark-etching rim that occurs at the high nickel border of taenite fields in iron meteorites and mesosiderites. Transmission electron microscopy (TEM) shows it to consist of a foam-like association of interpenetrating single crystals of taenite and kamacite when well developed(1) with an orientation relationship between those of the Kurdjumow-Sachs and the Nishiyama(2). It occurs between compositional limits that have been reported as approximately 25-40% Ni(1) and 30-40% Ni(3). Observed taenite particle sizes range from 0.4 microm in the Estherville mesosiderite(1) to considerably less than 0.1 microm for many iron meteorites (unpublished data). The mechanism of cloudy taenite formation has not been previously explained, although it is believed(2) to be a phenomenon related to the Invar effect, which occurs in Fe-35% Ni (Invar) and several other alloy systems. Santa Catharina is a wholly taenitic anomalous iron meteorite that contains 35% Ni and 0.6% Co (ref. 4). This composition, which is very similar to that of Invar, places it well inside the range where cloudy taenite is known to form. The optical microstructure of Santa Catharina suggested that the matrix phase of the entire meteorite may consist of cloudy taenite, so I have now examined it by TEM and the results are reported here.     

Zero thermal expansion in YbGaGe due to an electronic valence transition

Most materials expand upon heating. Although rare, some materials expand on cooling, and are said to exhibit negative thermal expansion (NTE); but the property is exhibited in only one crystallographic direction. Such materials include silicon and germanium at very low temperature (<100 K) and, at room temperature, glasses in the titania-silica family, Kevlar, carbon fibres, anisotropic Invar Fe-Ni alloys, ZrW2O3 (ref. 4) and certain molecular networks. NTE materials can be combined with materials demonstrating a positive thermal expansion coefficient to fabricate composites exhibiting an overall zero thermal expansion (ZTE). ZTE materials are useful because they do not undergo thermal shock on rapid heating or cooling. The need for such composites could be avoided if ZTE materials were available in a pure form. Here we show that an electrically conductive intermetallic compound, YbGaGe, can exhibit nearly ZTE--that is, negligible volume change between 100 and 400 K. We suggest that this response is due to a temperature-induced valence transition in the Yb atoms. ZTE materials are desirable to prevent or reduce resulting strain or internal stresses in systems subject to large temperature fluctuations, such as in space applications and thermomechanical actuators.     

化学镀CuNiP-碳纳米管复合材料的制备与表征

用化学镀的方法在多壁碳纳米管表面沉积Cu—Ni—P合金,制备碳纳米管复合材料．并对制备出来的复合材料进行透射电子显微镜（TEM）和X-射线衍射（XRD）表征．通过XRD对已制备的化学镀合金分析．得出沉积铜为立方面心结构而镍是非晶态．TEM观察复合碳纳米管,发现在其表面沉积有分散均匀纳米级的金属颗粒,Cu-Ni-P合金呈球形．     

Effect of stoichiometry and Cu-substitution on the phase structure and hydrogen storage properties of Ml-Mg-Ni-based alloys

To improve the electrochemical properties of rare-earth-Mg-Ni-based hydrogen storage alloys, the effects of stoichiometry and Cu-substitution on the phase structure and thermodynamic properties of the alloys were studied. Nonsubstituted Ml_0.80Mg_0.20(Ni_2.90Co_0.50-Mn_0.30Al_0.30)_x (x=0.68, 0.70, 0.72, 0.74, 0.76) alloys and Cu-substituted Ml_0.80Mg_0.20(Ni_2.90Co_0.50-y Cu_y Mn_0.30Al_0.30)_0.70 (y=0, 0.10, 0.30, 0.50) alloys were prepared by induction melting. Phase structure analysis shows that the nonsubstituted alloys consist of a LaNi₅ phase, a LaNi₃ phase, and a minor La₂Ni₇ phase; in addition, in the case of Cu-substitution, the Nd₂Ni₇ phase appears and the LaNi₃ phase vanishes. Thermodynamic tests show that the enthalpy change in the dehydriding process decreases, indicating that hydride stability decreases with increasing stoichiometry and increasing Cu content. The maximum discharge capacity, kinetic properties, and cycling stability of the alloy electrodes all increase and then decrease with increasing stoichiometry or increasing Cu content. Furthermore, Cu substitution for Co ameliorates the discharge capacity, kinetics, and cycling stability of the alloy electrodes.     

机械合金化法制备Cu-Ti-Zr基非晶合金

采用机械合金化法成功制备Cu40Ti60-xZr(x=0,10,30,50)非晶合金.研究Cu-Ti-Zr合金粉末由晶态向非晶态转变过程中的组织结构变化,探讨非晶合金的形成机制,以及非晶合金的热稳定性和晶化产物.结果表明,非晶合金直接从初始元素得到,在反应过程中没有金属间化合物出现,非晶化过程可以由间隙扩散模型来解释.Cu40TixZry非晶粉末的DSC分析表明,随着Ti含量的降低和Zr含量的升高,非晶粉末的晶化温度Tx逐渐升高,对非晶粉末在相应的Tx温度附近退火15min后发现,Cu40Ti30Zr30合金没有析出相,Cu40Ti1Zr50析出了Zr2Cu,Cu4Ti和少量的一些未知相.     

Zr基大块非晶的研究

利用射流成型法制备出Ｚｒ５２．５Ｃｕ１４．６Ａ１１０Ｔｉ５大块非晶,该合金系统具有很强的玻璃形成能力和宽的过冷区,其玻璃转化温度Ｔｇ＝６５０．６３Ｋ,晶化温度Ｔｘ＝７２１．９０Ｋ,过冷区△Ｔｘ＝Ｔｘ－Ｔｇ＝７１．２７Ｋ,Ｖｉｃｋｅｒ硬度为５５８ｋｇ／ｍｍ＾２,压缩断裂强度１７３０ＧＰａ,弹性模量８２ＧＰａ,观察其断口有大量纹络状河流花样,并有融化的液滴存在,该合金系统大的玻璃形成能力应归功于合金组     

几种Fe－Ni基非晶态合金的穆斯堡尔谱研究

作者利用穆斯堡尔诺对几种Ｆｅ－Ｎｉ基非成态合金进行了研究．通过对相应的越精细参数及越精细场分布的分析和讨论，得到了有关结构信息．     

Y_2Fe_(17)C_X合金的结构和磁性研究

本文用X射线衍射和磁测量及~(57)Fe穆斯堡尔谱研究了Y_2Fe_(17)C_x合金的晶体结构和磁性。碳原子在Y_2Fe_(17)C_x合金中占据六方结构的6h晶位或菱形结构的9e晶位;C原子的加入使得Y_2Fe_(17)C_x合金的居里温度和饱和磁化强度都有较为明显的变化,特别是近邻于C原子的Fe原子外层电子结构受到较大的影响。     

钇对ZrCuNiAl系合金非晶形成能力的影响

利用X射线衍射(XRD)和差示扫描量热分析(DSC)研究了添加钇对Zr55 Cu30Ni5Al10Y(=0,1,2,3,4)非晶合金体系玻璃形成能力的影响。用铜模铸造获得的Zr55 Cu30Ni5Al10Y(=0,1,2,3,4)块体非晶合金的临界尺寸从直径6 mm增加到20 mm。分析认为,微量钇的添加可以与合金中的残留氧形成氧化物,降低氧对合金形成非晶态结构的负面效应。因此添加适量的稀土元素钇有利于提高Zr55 Cu30Ni5Al10Y非晶合金体系的玻璃形成能力。