纳米Cu-Sn金属间化合物的制备及形成机理

以CuCl2.2H2O和SnCl2.2H2O为原料,NaBH4为还原剂,采用溶剂热法制备Cu10Sn3、Cu3Sn和Cu6Sn5金属间化合物。利用XRD、TEM、SAED对产物的物相、形貌及结构进行表征,考察了溶剂及原料配比对Cu-Sn金属间化合物形成的影响。结果表明,制备的三种产物颗粒尺寸分别为100~150nm、150~200 nm和300 nm;合金化进程是通过原子间相互吸附与扩散实现;反应初始阶段生成Cu10Sn3和Cu3Sn,其中Cu10Sn3是亚稳态,易转变为Cu3Sn。随着反应的继续进行,由于Sn原子不断向Cu3Sn扩散而最终形成Cu6Sn5。     

Electrocatalytic Formation and Inactivation of Intermetallic Compounds in Electrorefining of Silicon

Silicon for solar cell purposes is today produced by an energy intensive process exhibiting high irreversible thermodynamic energy losses. The purity of the product; 99,9999999 pct (9N), far exceeds what is generally accepted to be the requirements for photovoltaic purposes (4-6N). According to thermodynamics, all elements except boron may be removed from silicon by three layer electrochemical refining above the melting point of Si. Boron, on the other hand, shows higher affinity to specific transition metals compared to silicon. This may be exploited by applying two principles in parallel; electrochemical refining and electrocatalyzed reaction-precipitation of transition metal borides as heavy, stable particles. In this study we report on the formation of such compounds at the cathode-electrolyte interface during electrochemical refining. The trends and mechanisms observed in the laboratory scale investigation indicate that high purity silicon may be produced in industrial scale reactors at low cost- and energy intensity.     

机械合金化制备Ti-Al-Si纳米金属间化合物

4种成分的Ti-Al-Si颗粒T3,T4,T5和T6通过球磨获得非晶.这些非晶在退火时的结构变化分为3个阶段:(1)球磨非晶的部分晶化并产生Ti₅Si₃;(2)其余非晶的完全晶化并依赖于颗粒中Ti和Al的组成产生钛铝金属间化合物,(3)粉末中各相的晶粒长大.晶化反应依粉末成分产生Ti₃Al,TiAl和Al₃Ti.Ti₅Si₃是晶化反应的唯一硅化物.低于800℃退火可获得纳米晶。     

金属间化合物及其应用

主要介绍金属间化合物发展过程,讨论了该材料的特点、制造方法及应用情况.     

金属间化合物的机械合金化制备

综述了机械合金化制备金属间化合物的研究进展，指出了机械合金化技术在金属问化合物制备方面的优势。简述了机械合金化形成金属问化合物的机理，重点介绍了平衡相金属间化合物、弥散强化金属问化合物、过饱和金属问化合物，非晶合金、纳米晶材料等几类机械合金化金属间化合物的制备与组织性能。并针对目前研究的不足以及该研究领域的发展方向提出了加强MA过程热力学和动力学的基础理论研究、改良MA工艺等建议．     

Mechanism of Diffusion in Intermetallic Compounds

In a previous paper appearing in this journal (Tiwari and Mehrotra, Metall. Mater. Trans. A, vol. 43A, 2012, pp. 3654–62), the present authors advanced the hypothesis that the six-jump vacancy cycle, triple-defect mechanism, and antistructure bridge mechanism cannot explain the incidence of Kirkendall effect in B2 intermetallic compounds and hence their suitability as the operative mode of diffusion in these systems rests on dubious foundation. In the preceding contribution, Belova and Murch (BM) contested our hypothesis. This article is a reply to the BM’s critique of our paper.     

爆炸焊接和金属复合材料

简述了金属爆炸焊接的过程和它的金属物理学本质。总结了它的特点和应用,介绍了用爆炸焊接法生产的金属复合材料的品种和分类,由于此项技术可观的经济价值,将会在我国具有广阔的应用前景。     

齿科银汞合金材料中的金属间化合物

从材料学角度介绍了齿科银汞合金中各种金属间化合物的基本特征。简要评述了合金中金属间化合物对材料基本性能的影响。指出高铜银汞合金材料应进一步加强汞合反应机理、各相基本性能及合金材料物理性能等三方面的研究。     

Micropyretic Synthesis of Refractory Metal Intermetallic Compounds

The processing of refractory metal intermetallic compounds by micropyretic synthesis has been discussed in this article. The advantages of this process have been elaborated with the synthesis of intermetallic compounds in view. Microstructures of the synthesized alloys have been examined in detail and compared with the conventionally produced microstructure. The effect of different process parameters on the process and on the synthesized microstructure has been described. Special emphasis is given on the synthesis of aluminides of Nb and Ti and NiTi. The mechanism of micropyretic synthesis of the aforementioned intermetallic compounds from elemental powders has been studied by arresting the synthesis process midway. This has resulted in preservation of the unsynthesized material on one side, the fully synthesized material on the other and intermediate stages of synthesis frozen in between. A detailed microstructural characterization has been carried out around the arrested synthesis front in order to establish the sequence of synthesis.     

Micropyretic Synthesis of Refractory Metal Intermetallic Compounds

Abstract

The processing of refractory metal intermetallic compounds by micropyretic synthesis has been discussed in this article. The advantages of this process have been elaborated with the synthesis of intermetallic compounds in view. Microstructures of the synthesized alloys have been examined in detail and compared with the conventionally produced microstructure. The effect of different process parameters on the process and on the synthesized microstructure has been described. Special emphasis is given on the synthesis of aluminides of Nb and Ti and NiTi. The mechanism of micropyretic synthesis of the aforementioned intermetallic compounds from elemental powders has been studied by arresting the synthesis process midway. This has resulted in preservation of the unsynthesized material on one side, the fully synthesized material on the other and intermediate stages of synthesis frozen in between. A detailed microstructural characterization has been carried out around the arrested synthesis front in order to establish the sequence of synthesis.     

NiAl金属间化合物超塑性研究

研究了NiAl金属间化合物在拉伸条件下的超塑性变形行为和机理.结果表明用常规精铸工艺和定向凝固工艺制备的NiAl及NiAl基合金都表现出典型的超塑性特征.根据这些合金的显微组织的特点可以分为3类多相等轴晶组织(NiAl-9Mo,NiAl-25Cr,NiAl-20Fe-Y、Ce,NiAl-30Fe-Y);单相等轴晶组织(NiAl)和柱状晶组织(NiAl-27Fe-3Nb,NiAl-15Cr,NiAl-5Mo-0.5Hf).相应的超塑性变形机理分别是晶界滑动伴随着动态回复,动态回复和再结晶以及晶内的位错滑移.     

爆炸焊接与金属材料的保护

用爆炸焊接技术生产的许多带有耐蚀复层的金属复合材料，能够卓有成效地解决生产和科学技术中大量的金属材料的保护问题。以大量实例综述了爆炸焊接和爆炸复合材料在金属材料保护中的应用。     

金属间化合物电学性能的研究进展

金属间化合物具有高强轻质及电阻率较高的特点,是一种极具发展前途的功能材料.文章对近几年金属间化合物电学性能的研究和应用进行了总结,分析了其电学性能的影响因素,并对其以后的研究和发展方向进行了展望.     

The Electrochemical Formation of Ni-Tb Intermetallic Compounds on a Nickel Electrode in the LiCl-KCl Eutectic Melts

The work presents an electrochemical study on the formation of Ni-Tb intermetallic compounds in the LiCl-KCl-TbCl₃ melts on tungsten and nickel electrodes at 773 K (500 °C) by electrochemical techniques. For a tungsten electrode, cyclic voltammetry and square-wave voltammetry showed that the electrochemical reduction of Tb(III) proceeded in a one-step process involving three electrons at ?2.06 V (vs Ag/AgCl). For a nickel electrode, the reduction potential of Tb(III)/Tb was observed at more positive values than those on W electrode by cyclic voltammetry, due to the formation of Ni-Tb intermetallic compounds. Square-wave voltammetry and open-circuit chronopotentiometry put into evidence the formation of intermetallic compounds at around ?1.27, ?1.63, and ?1.88 V, respectively. Three alloy samples were obtained by potentiostatic electrolysis on a Ni electrode at various potentials and analyzed by X-ray diffraction, scanning electron micrograph, and energy-dispersive spectrometry. The analysis results confirmed the formation of Ni₁₇Tb₂, Ni₅Tb, and Ni₂Tb alloy compounds.     

Mechanical Properties of Diverse Binary High-Temperature Intermetallic Compounds

A suite of 29 binary, single-phase alloys that includes 18 different ordered intermetallic crystal structures has been tested. Microhardness and tendency toward formation of cracks are reported as a function of temperature; room-temperature Young’s moduli are quoted; and results of simple room-temperature toughness tests are given. Using toughness, low specific gravity, and hardness at 1000 °C as figures of merit, several alloy systems are recognized as deserving of more concentrated study.     

Synthesis of Intermetallic Compounds by Using Lithium Hudride

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