Existence Of Intermetallic Compounds Research Articles

Morphology-tunable synthesis of CuO modified with Cu-Zn/Cu-Sn intermetallic compounds as high-performance anode for lithium-ion batteries

CuO anode modified with intermetallic compounds is conducive to improve its electrochemical performance by enhancing conductivity and structure stability. Herein, CuO modified with Cu5Zn8 and Cu10Sn3 intermetallic compounds, denoted as ZnSn/CuO, was synthesized by etching bronze powder with ammonia solution, and its morphology can be easily controlled by adjusting the content of ammonia solution. The obtained hollow wool-ball-like ZnSn/CuO constructed with nanosheets has a high reversible capacity of 846.9 mA h g−1 after 200 cycles at a current density of 500 mA g−1. ZnSn/CuO achieves excellent rate performance and cycling stability due to the improved conductivity and buffered volume expansion, benefiting from the existence of intermetallic compounds and unique nano-structure mechanism. Therefore, the outstanding electrochemical property and this novel synthesis route make ZnSn/CuO become a potential anode material for lithium-ion batteries.

Influence of Al-3Ti-0.15C and Ce on Microstructure and Tensile Properties of Al-Si-Cu 319 alloy

In the present research, an attempt has been made to evaluate the effects of addition of Al-3Ti-0.15C (0.05wt%) master alloy with different concentration (0.1, 0.3, 0.5, 0.8, 1wt%) of cerium (Ce), a rare earth element on microstructure and tensile properties of Al-Si-Cu 319 alloy. Optical microscopy (OM) and field emission scanning electron microscopy (FE-SEM) with EDS analysis was employed to study the microstructural modification and existence of intermetallic compounds. Experimental results show that addition of Ce with up to 0.3wt% increases the tensile properties up to 49.13% as compared to base alloy due to refinement of α-Al and modification of eutectic silicon. In contrast, tensile properties decline above 0.3wt% addition of Ce due to formation of needle like intermetallic compounds. These Ce rich needles like intermetallic compounds suppress the effect of modification, decreasing tensile properties of modified alloy.

Corrosion behavior of Sn-3.0Ag-0.5Cu alloy under chlorine-containing thin electrolyte layers

Corrosion behavior of Sn-3.0Ag-0.5Cu lead-free solder alloy under chlorine-containing thin electrolyte layers is studied. The emphasis is laid on discussion about influences of addition of alloying elements, concentration of chloride ion and thickness of electrolyte layer on its corrosion behavior. Results indicate that: mainly local corrosion occurs to the alloy; Existence of intermetallic compounds and β-Sn crystal boundary facilitates the process of Cl− infiltration into the base and galvanic corrosion. Metal ions are accumulated in pitting corrosion region, and hydrolysis of metallic ions promotes the solution acidification and transverse development of pitting corrosion.

A dislocation density based micromechanical constitutive model for Sn–Ag–Cu solder alloys

Based on the dislocation density hardening law, a micromechanical model considering the effects of precipitates is developed for Sn–Ag–Cu solder alloys. According to the microstructure of the Sn–3.0Ag–0.5Cu thin films, intermetallic compounds (IMCs) are assumed as sphere particles embedded in the polycrystalline β-Sn matrix. The mechanical behavior of polycrystalline β-Sn matrix is determined by the elastic–plastic self-consistent method. The existence of IMCs not only impedes the motion of dislocations but also increases the overall stiffness. Thus, a dislocation density based hardening law considering non-shearable precipitates is adopted locally for single β-Sn crystal, and the Mori–Tanaka scheme is applied to describe the overall viscoplastic behavior of solder alloys. The proposed model is incorporated into finite element analysis and the corresponding numerical implementation method is presented. The model can describe the mechanical behavior of Sn–3.0Ag–0.5Cu and Sn–1.0Ag–0.5Cu alloys under high strain rates at a wide range of temperatures. Furthermore, the overall Young’s modulus changes due to different contents of IMCs is predicted and compared with experimental data. Results show that the proposed model can describe both elastic and inelastic behavior of solder alloys with reasonable accuracy.

Formation of intermetallic compounds and their effect on mechanical properties of aluminum–titanium alloy films

AbstractAl–Ti alloy films with various Ti contents were prepared through magnetron co-sputtering with Al and Ti targets and treated with vacuum annealing at 400 °C. Energy dispersive spectroscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and nanoindentation were used to determine the composition, microstructure and hardness of the films to reveal the existence of intermetallic compounds and their effects on the microstructure and mechanical properties. The results showed that Al–Ti films with lower Ti contents formed nanocrystalline structures of highly supersaturated solid solution. With the increase of Ti content, various types of Al–Ti intermetallic compound bonds formed. The existence and increasing concentration of these compound bonds gradually transformed the films into amorphous structures and supported the continual increase of the film hardness, reaching a high value of 8.8 GPa at 36.3 at.% Ti.

Interfacial Microstructure and Phase Constitution of the Cu/Al Dissimilar Metals Joint Made by Contact Reactive Brazing

Joining Cu to Al has been carried out by vacuum contact reactive brazing without filler metal. Experimental results obtained showed that the eutectic structure and some Cu-Al intermetallic compounds were the main phases of the braze seam. The fracture surface of the joint presented typical brittle fracture for the existence of intermetallic compounds at the interface and the shear strength could reach 65MPa.

ФормированиЕ интерметаллидоВ В металлическиХ сплаваХ прИ электрохимическоЙ крИсталлИзацИИ

On the basis of model experiments the formation of intermetallic compounds in metal alloys during electrocrystallization was found. The existence of intermetallic compounds in electrodeposited alloys proves the validity of the concept that metallic materials in the process of electrochemical crystallization pass through a stage of liquid state.

Relationship of glass formation ability and eutectics in ternary Ni–Zr–B system

Five Ni–Zr–B ternary eutectic alloys were synthesized by means of melt spinning and were found “amorphous” by standard surface x-ray diffraction. The thermal stability was determined by differential scanning calorimetry. Glass-formation ability (GFA) was characterized by reduced glass transition temperature among the five “amorphous” alloys. The existence of intermetallic compounds which are structurally complex and have bigger lattice parameters is proved to enhance the higher GFA. The effective suppression of nucleation and growth of intermetallic compounds plays a very important role for the glass formation.

界面偏析を利用したコーティング膜／母材界面改質法

A technique to modify interface after the formation of interface is desired either from a process requirement or because of the change of material use with time. A novel technique to form an intermetallic compound at the interface between coated layer and substrate by depositing a chosen metal film on the top of a coated layer is presented. The diffusion and interfacial reaction of specimens with top-film/middle-film/substrate structure were investigated. With proper choice of top-film element, top-film element diffused inside without detectable reaction with middle-film and concentrated at the interface between middle-film and substrate followed by intermetallic compound formation. We discuss conditions for obtaining above phenomena and general guide for a choice of top-film element is presented. Key factors are (1) segregation tendency of top-film element on middle-film metal, (2) activation energy of diffusion of top-film element in middle-film and in substrate, and (3) existence of intermetallic compound between top-film metal and substrate in phase diagram. The examples of intermetallic compound formation by the diffusion of top-film element are given in Ti-film/Nb-film/Cu-substrate, Fe-film/Nb-film/Ti-substrate, Cu-film/Fe-film/Zr-substrate, and Fe-film/Zr-film/Ti-substrate.

Relation between potential of binary liquid alloys and composition of intermetallic compounds contained therein

For systems of binary liquid alloys for which the existence of defined intermetallic compounds in the solid state had been proved, a theoretical expression was derived for the relation between the electrode potential and the composition of liquid alloys under the assumption that intermetallic compounds can exist even in liquid alloys. It was further shown that, for limited conditions, such a relation is of the same form as that obtained for binary systems on the basis of the theory of regular solutions if no formation of intermetallic compounds is considered. These results lead to the conclusion that the validity of the relation based on the theory of regular solutions of simple binary systems is far from being a proof that the existence of intermetallic compounds in such liquid binary alloys is impossible.

Prediction of transition metal phase diagrams

Abstract The design of nuclear fuels and their containers, moderating materials of reactors, heat-exchanger materials, fission-product control, and fuel processing systems requires knowledge of the thermodynamics and phase relations not only of the actinide elements and their compounds but also of many other elements of the periodic table, particularly the transition metal elements. The present discussion which deals with methods of predicting the thermodynamics and phase diagrams of the transition metals, lanthanides, and actinides is based largely on the first three references. These publications provide additional references that give more detail. The fourth reference, dealing with the existence of intermetallic compounds of extraordinary stability, may also be of interest. A paper by Sasaki entitled “Alloy Design” provides an example published in Japanese of the application of the ideas to be discussed. It is not possible in the space allotted to cover the methods of predicting transition metal phase diagrams in great detail. The general principles will be reviewed and some sample applications illustrated.

Nuclear magnetic resonance of115In and209Bi in some liquid binary alloys

The Knight shift of the 115In resonance has been measured as a function of composition in the liquid alloy systems In-Cd, In-Hg, In-Tl, In-Sn, In-Pb and In-Bi, and of the 209Bi resonance in In-Bi. The changes in shift follow no simple pattern and show no correlation with valency difference or ionic size difference. The results are not explicable by the theory of electron density fluctuations used successfully by Blandin and Daniel to explain changes in shift in silver-base solid solutions. The results for In-Bi point to the existence of intermetallic compounds in the liquid state. Linewidths are consistently larger than expected from the Korringa relation, probably owing to electric quadrupole interactions.

The existence of intermetallic compounds in the vapor state. The spectra of the alkali metals, and of their alloys with each other

The existence of intermetallic compounds in the vapor state. The spectra of the alkali metals, and of their alloys with each other

The existence of intermetallic compounds in the vapour state. The spectra of the alkali metals, and of their alloys with each other

It has been uncertain until recently, whether any of the many intermetallic compounds which have been established in liquid and solid alloys can persist into the vapour state, or whether they invariably dissociate into mere mixtures of the individual metal vapours. Volatile compounds have occasionally been suspected ( e. g ., between magnesium and zinc) on account of the deposition of typical crystals of compounds during the distillation of an alloy of the two metals, but such evidence is so indirect that it carries little weight. The most promising way of approaching this question is by a study of the absorption spectra of mixtures of metallic vapours. The metals that are known to possess a measurable proportion of diatomic or polyatomic molecules in the vapour state invariably indicate this property by the appearance of bands in their absorption spectra. In fact, since it has been accepted that band spectra cannot originate from single atoms, the observation of such bands has become the most delicate test for the existence of association in the vapours. For example, the usual methods of molecular weight determination have led to the belief that the alkali metal vapours are solely monatomic. This cannot, however, be true, as each of these metals possesses an extensive band spectrum, which appears at quite low vapour pressures. There can be no doubt, on the basis of this spectroscopic evidence, that an appreciable fraction of the molecules in the vapour of boiling sodium, etc., are di- (or poly-) atomic. This point will be discussed fully below.