微细钨铜复合粉的制备及其烧结过程的研究

以 WO_3和 CuO 为原料的焙烧-还原法能制取钨颗粒细小(0.1～0.5μm)且 W、Cu 分布均匀的复合粉.此粉末压制、烧结性能良好,可翻取钨晶粒为0.8～1.0μm 的 W-Cu 假合金,合金的相对密度可达98%～99%.研究了 CuWO_4的生成及其氢还原过程,发现它与 WO_3 相比,氢还原相变及其动力学过程存在某些差异.用不同方法翻取的钨铜复合粉的特性及其成型、烧结工艺对合金综合性能的影响进行了比较,指出用焙烧-还原法制取的钨铜复合粉具有优良的工艺特性.     

扩散合金粉末的制备与性状表征

本文以鞍钢粉材厂生产的水雾化铁粉(FSY200.3)为原料,钼酸铵、乙酸铜、乙酸镍为包覆剂,通过水溶液浸泡-氢气还原的方法使所需金属均匀扩散于水雾化铁粉表面。实验考察了制取含有被包覆金属铁粉的详细过程;确定了合金粉末Fe-Mo-Ni-Cu生产的最佳工艺条件。对还原后的合金粉末进行了扫描电镜和能谱的表征。用分光光度计检测了合金粉末中各元素的含量。测定了还原后合金粉末的松装密度、流动性、压缩性和氢损等指标。结果表明:水溶液浸泡-氢气还原法制备的合金粉末各项工艺参数均能达到指标要求。将实验制得的合金粉末(HJ)分别添加不同质量分数的碳粉,测其硬度、拉伸强度并与相同条件下的合金粉末(FSY-01K)进行对比,其硬度和拉伸强度均高于传统方法制备的合金粉末。     

线材轧机铜钨合金导卫的研制

介绍了铜钨合金材料的特性以及铜钨合金导卫的制作工艺、使用设备和产品优点，并详细阐述了铜钨合金导卫的压制原理、烧结致密化机理和自润滑机理。     

含铜硫化金矿的综合利用

用氯化铜水溶液浸出法回收硫代硫散盐浸金渣中铜，可在常压、１００℃以下温度操作。铜银回收率都比用浮选法高。在比较三种工艺过程的基础上，对含铜硫化金精矿提出氯化铜溶液浸铜一硫代硫酸盐液浸金的综合处理工艺。     

简讯

日本大力开发改良型镍钛系记忆合金在形状记忆合金材料中，镍－钛系合金是性能最优且用途最广的一种。镍－钛系合金的延展性、形状记忆强度、应变、耐蚀性及稳定性都很好，但其成本较高。近年来，日本致力于开发一系列改良型镍－钛合金，通过添加其它元素进一步改善其性能，并降低成本。如添加铜或钒、铝、铬、锆可大大改善其韧性、加工性和切削性；在镍－钛－铜系合金中添加稀土元素和硼、硅、磷和硫等，可制成回复特性明显增强的形状记忆合金。日本住友电气工业公司在镍－钛合金中添加铜（或铝、锆、钒、钴、铁）元素后，经表面深层处理后…     

熔渗法制备W-Yb合金及其性能的研究

稀土元素镱活性极高,极易氧化,且蒸汽压很高,在钨铜、钨银合金的研究基础上对钨镱假合金进行了研究,通过前期对钨粉粒度、实验工艺等的优化后,采用冷等静压(200 MPa压力)压制烧结制备钨骨架,1000℃氢气还原预烧结、1800℃真空烧结,氩气气氛保护熔渗稀土镱制备钨镱合金,综合其密度,硬度等基本实验数据,分析了钨镱合金的组织.结果表明:制备出了高致密度的钨镱合金,钨镱合金密度为15.30 g·cm<'-3>,相对密度达到99.5%以上,硬度值低于HRB82,所制备的钨骨架其通道分布均匀,经熔渗法制备的钨镱合金中镱元素的分布呈现大面分布均匀,高倍状态下出现局部富集的情况,其富集情况与钨骨架通道分布情况相符合.所制备的钨镱合金能够满足特殊要求应用于配套材料.     

新技术与新成果

200409从含钨废料中回收钨的新工艺美国一家公司研究出一种从含钨废料中回收钨的新工艺。该工艺的过程是:首先用氢氧化钠溶液蒸煮含钨废料,生成钨酸钠溶液,结晶出钨酸纳晶体;然后将钨酸钠晶体溶解于循环的母液中,重新生成钨酸钠溶液;再用有机萃取剂萃取钨,纯化得钨酸铵,蒸发形成仲钨酸铵和含有钨、硅、砷、磷和钼的母液,母液可循环使用。这种工艺的优点是,母液可以循环使用,避免了过去工艺过程中会释放出大量铵盐的问题。200410泡沫镍(铜)与镍网(毡)生产设备一种泡沫镍(铜)与镍网(毡)生产设备,属于电化学技术领域。主要解决现有设备镀镍(铜)…     

KF－B_2O_3－K_2WO_4熔体中电镀钨的研究─—周期反向电流（PRC）

采用周期反向电流技术对ＫＦ－Ｂ＿２Ｏ＿３－Ｋ＿２ＷＯ＿４熔盐体系中钨的电镀工艺进行了研究。实验结果表明：当温度为８００℃时，在钼、铜和镍基体上均可获得平整致密、与基体结合性好、呈银灰色的钨镀层，其中在钼基体上镀层最厚可达约２１０μｍ。ＸＲＤ分析表明：在以上三种基体上钨均沿［１１０］和［２１１］方向形成织构。镀层断面元素线扫描分析表明：钨镀层与钼基体之间未形成扩散层。     

W－Ni－Cu合金的断口缺陷与工艺因素分析

在对Ｗ－Ｎｉ－Ｃｕ合金断口形貌的观察中，发现合金材质内部存在着孔隙、驻化、成分偏析等缺陷，本文分析了产生这些缺陷的有关工艺因素，并进一步探讨了Ｗ－Ｎｉ－Ｃｕ合金的制备工艺。     

氯化铜钾法在测定钴冰铜、高冰镍中合金相的应用

转炉渣电炉贫化缓冷钴冰铜的主要成分是:铁钴镍合金、陨硫铁(FeS)和少量镍钴的硫化物;高冰镍中的二硫化三镍则相当高.该产品的金属化率是选冶工艺的主要参数之一.氯化铜-乙醇法,合金相浸取不完全;氯化铜-甲醇法分离效果尚可,但浸取时间长达3小时,甲醇易挥发,有害人体,不适宜大批样品分析.文献提出的氯化铜钾法,曾用于炉渣和陨铁中金属相的测定,试验证明,此法也可用于分析钴冰铜及其选矿产品和含有铜镍合金及二硫化三镍的低硫高冰镍中的合金相.     

添加钕对Mg2Ni储氢合金的结构和电极性能的影响

利用两步法制备了一系列添加Nd的三元Mg2-xNdxNi合金。XRD分析证实，当x=0．05，0．1时，制得的三元Mg2-xNdxNi合金均为Mg2Ni单相合金；三元Mg18Nd0．2Ni(x=0．2，0．3)合金为三相合金，三相分别为Mg2Ni，NdNi，NdMgNi4。模拟电池测试结果表明，同Mg2Ni合金相比，球磨10h的三元Mg1．8Nd0．2Ni合金和Mg17Nd03Ni合金电极的放电容量提高明显，且Mg17Nd03Ni合金电极的循环性能有明显改善。这极有可能与合金中NdMgNi4相的存在以及球磨形成的微结构有关。     

Reaction behavior of Ni–Re alloys during direct current polarization in sulfuric acid solutions

The macrokinetic regularities of the reactivity of synthesized Ni–Re (20 and 60 wt %) alloys in a sulfuric acid solution (100 g/L, 25–40°C) during direct current polarization are studied using physicochemical methods. The phase composition of the synthesized alloys is determined by the formation of solid solutions as a function of the initial Ni/Re weight ratio. These are two types of nickel solid solutions (Ni₁₆Re_0.2 and Ni₁₄Re_0.9) and one rhenium solution (Ni_1.1Re). These solid solutions are anodically oxidized in the sequence of their structural rearrangement Ni₁₆Re_0.2 → Ni₁₄Re_0.9 → Ni_1.1Re with a combined transition of the metals into an electrolyte solution. These solid solutions provide the reduction of Ni³⁺ to Ni²⁺ due to the depolarization ability of rhenium, being their component.     

晶粒细化对Cu-40Ni合金在酸性含Cl-介质中耐蚀性能的影响

采用电弧熔炼（CA）和机械合金化（MA）通过热压烧结工艺制备了晶粒尺寸差别较大的Cu-40Ni合金，借助于PARM273A和M5210电化学综合测量仪，利用动电位扫描法和交流阻抗技术对比研究了上述合金在酸性含Cl^-介质中的腐蚀电化学性能以及腐蚀机制。结果表明：两种合金的腐蚀电位随时间逐渐稳定，在中性Na2SO4溶液中加入H2SO4和NaCl后，两种合金的自腐蚀电位负移；晶粒细化后，两种合金的自腐蚀电位则正移。两种合金在中性及酸性含Cl^-介质中均存在钝化现象，但在酸性含Cl^-介质中钝化区间很短，钝化能力较弱。两种合金的交流阻抗谱均由单容抗弧组成，反应由电化学过程控制。晶粒细化后，合金中存在大量晶界，参与腐蚀反应的活性原子数增加，促使MACu40Ni合金的腐蚀速度高于CACu-40Ni合金。     

Microstructure and phase identification in type 304 stainless steel-zirconium alloys

Stainless steel-zirconium alloys have been developed at Argonne National Laboratory to contain radioactive metal isotopes isolated from spent nuclear fuel. This article discusses the various phases that are formed in as-cast alloys of type 304 stainless steel and zirconium that contain up to 92 wt pct Zr. Microstructural characterization was performed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), and crystal structure information was obtained by X-ray diffraction. Type 304SS-Zr alloys with 5 and 10 wt pct Zr have a three-phase microstructure—austenite, ferrite, and the Laves intermetallic, Zr(Fe,Cr,Ni)_2+x. whereas alloys with 15, 20, and 30 wt pct Zr contain only two phases—ferrite and Zr(Fe,Cr,Ni)_2+x. Alloys with 45 to 67 wt pct Zr contain a mixture of Zr(Fe,Cr,Ni)_2+x and Zr₂(Ni,Fe), whereas alloys with 83 and 92 wt pct Zr contain three phases—α-Zr, Zr₂(Ni,Fe), and Zr(Fe,Cr,Ni)_2+x. Fe₃Zr-type and Zr₃Fe-type phases were not observed in the type 304SS-Zr alloys. The changes in alloy microstructure with zirconium content have been correlated to the Fe-Zr binary phase diagram.     

稀土化合物对粉末冶金镍基合金摩擦磨损性能的影响

用粉末冶金热压方法制备了几种含不同稀土化合物（LaF3,CeO2,La2O3)的Ni基合金，将合金制备为块样，45^#钢为环样，在环－块摩擦试验机上考察了稀土化合物含量及其种类对Ni基合金摩擦磨损性能的影响，研究结果表明：添加稀土化合物可明显改善合金在高载高速下的耐磨性能，这与其摩擦表面形成摩擦保护性“釉质层”密切相关。     

Incidence of spontaneous subarachnoid hemorrhage among Hispanics and non-Hispanic whites in New Mexico

Tri(gamma-glutamylcysteinylglycinyl)trithioarsenite (AsIII(GS)3) is formed in cells and is a more potent mixed-type inhibitor of the reduction of glutathione disulfide (GSSG) by yeast glutathione (GSH) reductase than either arsenite (AsIII) or GSH. The present work examines the effects of valence and complexation of arsenicals with GSH or L-cysteine (Cys) upon potency as competitive inhibitors of the reduction of GSH disulfide (GSSG) by yeast GSH reductase. Trivalent arsenicals were more potent inhibitors than their pentavalent analogs, and methylated trivalent arsenicals were more potent inhibitors than was inorganic trivalent As. Complexation of either inorganic trivalent As or methylarsonous diiodide (CH3As(III)I2) with Cys or GSH produced inhibitors of GSH reductase that were severalfold more potent than the parent arsenicals. In contrast, dimethylarsinous iodide ((CH3)2As(III)I) was a more potent inhibitor than its complexes with either GSH or Cys. Complexes of CH3AsIII with GSH (CH3-AsIII(GS)2) or with Cys (CH3AsIII(Cys)2) were the most potent inhibitors, with Ki's of 0.009 and 0.018 mM, respectively. Inhibition of GSH reductase by arsenicals or arsenothiols was prevented by addition of meso-2,3-dimercaptosuccinic acid (DMSA) to a mixture of enzyme, GSSG, and inhibitor before addition of NADPH. DMSA added to the reaction mixture after NADPH reversed inhibition by (CH3)2As(III)I but had little effect on inhibition by CH3As(III)I2, Ch3AsIII(GS)2, CH3AsIII(Cys)2, or AsIII(GS)3. Partial redox inactivation of the enzyme with NADPH increased the inhibitory potency of CH3As(III)I2 and (CH3)2As(III)I and changed the mode of inhibition for CH3As(III)I2 from competitive to noncompetitive. The greater potency of methylated trivalent arsenicals and arsenothiols than of inorganic trivalent As suggests that biomethylation of As could yield species that inhibit reduction of GSSG and alter the redox status of cells.     

Effect of oxide scale on carbon deposition on Fe-Ni alloys in carburizing gas

The behavior of carbon deposition on preoxidized Fe-Ni alloys containing 0 to 57.0 mass pct Ni in 10 pct CH₄-H₂ mixture at 1203 K was studied by metallography and thermogravimetry. Nickel retarded carburization and carbon deposition by lowering the solubility limit of graphite in austenite and by reducing catalytic activity for the pyrolytic reaction of CH₄. On oxidation in air, the addition of nickel to iron depressed the development of FeO and, thereby, caused a significant decrease in the thickness of the scale. The exposure of the alloys to 10 pct CH₄-H₂ mixture after the oxidation in air led to a sudden mass loss in the early stage and then a rapid mass gain. This mass change is primarily ascribed to mass loss by reduction of iron oxides and to mass gain by carbon deposition. The rapid mass gain by carbon deposition is probably due to the formation of active iron by reduction of iron oxides and to the increase in the reaction area by spallation of the scale; the active iron formed may promote filamentous carbon deposition through Fe₃C formation and decomposition. Carbon deposition on the alloys containing 27.2 mass pct Ni or more was considerably retarded because of the formation of a thin oxide scale which consists of α-Fe₂O₃ and spinel (Ni_xFe_3−xO₄) and the reduction of catalysis by enrichment of nickel in the subscale. However, the amounts of carbon deposition increased compared with those on the as-polished alloys, owing to the presence of reducible iron oxides.     

Metastable nanocrystalline nickel-boron alloys obtained by mechanical alloying

Ni-B and Ni-Nb-B alloys are produced by mechanical alloying of mixtures of Ni, Nb, and B powders. X-ray diffraction analysis of the alloys indicates the formation of Ni(B) and Ni(Nb, B) solid solutions with nanocrystalline structure. The phase composition of the alloys is studied at different stages of mechanical alloying, along with the thermal stability and the phase transformations on heating.     

稀土在Ni/MH电池中应用研究

综述了稀土在N i/MH电池中的作用机理。贮氢合金中稀土的含量和组成改变合金的微晶结构,影响合金的吸放氢特性。镍电极中掺杂稀土添加剂一方面可以有效地提高析氧过电位,改善N i/MH电池高温性能。另一方面稀土的掺杂使N i(OH)2晶格发生畸变,改善材料的质子扩散性能,减少电化学反应阻抗。此外,电解液中引入稀土化合物,可增大电极表面的活性中心。阐述了稀土是改善N i/MH电池性能的一种有效的活性材料和添加剂。     

Thermodynamics of Oxygen Solution in Fe–Ni Melts Containing Boron

Fe–Ni alloys are widely used in engineering today. They are sometimes alloyed with boron. Oxygen is a harmful impurity in Fe–Ni alloys. It may be present in dissolved form or as nonmetallic inclusions. The presence of oxygen in Fe–Ni alloys impairs their performance. Research on the thermodynamics of oxygen solutions in Fe–Ni melts containing boron is of considerable interest in order to improve alloy production. The present work offers a thermodynamic analysis of solutions of oxygen in Fe–Ni melts containing boron. The equilibrium constant of the reaction between boron and oxygen dissolved in the melt in such systems is determined. The activity coefficients at infinite dilution and the interaction parameters in melts of different composition are also calculated. When boron reacts with oxygen in Fe–Ni melts, the oxide phase contains not only B₂O₃ but also FeO and NiO. The mole fractions of B₂O₃, FeO, and NiO in the oxide phase are calculated for different boron concentrations in Fe–Ni melts at 1873 K. For iron melts with low boron content, the mole fraction of boron oxide is ~0.1. With increase in the nickel and boron content in the melts, the boron-oxide content in the oxide phase increases. Its mole fraction is close to one for pure nickel. The solubility of oxygen in Fe–Ni melts is calculated as a function of the nickel and boron content. The deoxidizing ability of the boron improve significantly with increase in nickel content in the melt. The curves of oxygen solubility in Fe?Ni melts containing boron pass through a minimum, which is shifted to higher boron content with increase in nickel content in the melt. The boron content at the minima on the curves of oxygen solubility are determined, as well as the corresponding minimum oxygen concentrations.