Cd Alloy Research Articles

Electrodeposition and characterization of Cu–Ni–Zn and Cu–Ni–Cd alloys

The electrodeposition of ternary Cu–Ni–Zn and Cu–Ni–Cd alloys was investigated in acidic sulphate electrolytes. The influence of Zn 2+ and Cd 2+ ions concentrations as well as the effect of current density on the surface appearance and the deposits’ composition was examined. Sodium dithiolate (NaS) 2C C(CN) 2·3H 2O was used as surface active substance (SAS), and the effect of the SAS on the alloys composition and surface morphology was also investigated. No significant effect of SAS on the alloy composition, however, apparently effect on the deposits surface morphology was observed. It was also noticed that on increasing Zn 2+ (or Cd 2+) concentration in the bath, a depletion in the nickel content in the deposit occurred. Deposits obtained were characterized from the structural and morphological points of view. It was found that the structure and morphology of the deposited alloys are mainly controlled by both the applied current densities and the bath composition.

Hot-working characteristics of a Pb-2 wt%Cd alloy during transformation

Stress-strain measurements were carried out on a Pb-2 wt%Cd alloy at different strain rates from 6.4×10 −4 to 1.0×10 −2 s −1 and in the temperature range from 433 to 503 K. The material's dynamic stress–strain response, strain rate, temperature effects and possible deformation mechanisms are discussed. The hot working parameters such as yield stress; ultimate stress, elastic modulus and the total strain were estimated as function of temperature and strain rate to evaluate the structural changes during transformation. Nevertheless, the effect of the transformation on the activation energy and the strain rate sensitivity parameter was studied. Furthermore, the microstructure of the studied samples was investigated below and above the transition temperature (0.65 T m) using optical microscopy and X-ray analysis.

A study of Bi–Pb–Sn–Cd–Sb penta-alloys rapidly quenched from melt

Optical microscopy, X-ray diffractometry, the double bridge method, the Vickers microhardness testing and dynamic resonance techniques have been used to investigate structure, electrical resistivity, hardness, internal friction and elastic modulus of quenched Bi–Pb–Sn–Cd–Sb penta-alloys. The properties of these penta-alloys are greatly affected by rapid quenching. The intermetallic compound χ(Pb–Bi) or Bi3Pb7 is obtained after rapid quenching using the melt-spinning technique, and this is in agreement with reports by other authors [Marshall, T. J., Mott, G. T. and Grieverson, M. H. (1975). Br. J. Radiol., 48, 924; Kamal, M., El-Bediwi, A. B. and Karman, M. B. (1998). Structure, mechanical properties and electrical resistivity of rapidly solidified Pb–Sn–Cd and Pb–Bi–Sn–Cd alloys. J. Mater. Sci.: Mater. Electron., 9, 425; Borromêe-Gautier, C., Giessen, B. C. and Grrant, N. J. (1968). J. Chem. Phys., 48, 1905; Moon, K.-W., Boettinger, W. J., Kattner, U. R., Handwerker, C. A. and Lee, D.-J. (2001). The effect of Pb contamination on the solidification behavior of Sn–Bi solders. J. Electron. Mater., 30, 45.]. The quenched Bi43.5Pb44.5Cd5Sn2Sb5 alloy has important properties for safety devices in fire detection and extinguishing systems.

Electrodeposition of a Cu–Cd Alloy in the Presence of Surfactant Mixtures from Several Reaction Series

The effects of one- to four-component mixtures of organic compounds from four reaction series on the currents and potentials of the electrodeposition of a Cu–Cd alloy were studied. The revealed correlation between the deposition parameters of compositionally different alloys and their constituents, on one hand, and the total polarity of substituents in surfactant molecules, on the other hand, was interpreted in terms of the Linear Gibbs Energy Relation.

Stress corrosion cracking of copper and silver, specific effect of the metal cations

Based on stress corrosion cracking (SCC) studies on brass, and on Ag–Cd alloys (a model alloy used to reproduce the behaviour of brass), it was found that both pure copper and pure silver are susceptible to SCC in 1 M copper(II) nitrate and in 1 M silver nitrate aqueous solutions, at the equilibrium potentials for the reactions: Cu 2++2e −↔Cu and Ag ++e −↔Ag, respectively. The results were analysed under the light of recent developments in surface science. It was concluded that the same SCC mechanism that operates in brass and in Ag–Cd alloys should be operating during SCC of pure copper and pure silver, under equivalent experimental conditions.

Alloy formation in the system Au(1 1 1)/Cd during the UPD process

The Au–Cd alloy formation in the course of Cd underpotential deposition (UPD) in the system Au(1 1 1)/Cd 2+, SO 4 2− has been studied by conventional electrochemical techniques and in situ STM. The long time polarization experiments and the current–potential desorption spectra have indicated that the alloy can be formed at relatively high underpotentials with the formation of 2D Cd islands as was observed by in situ STM images. These islands grow and coalesce at a constant potential with the subsequent formation of new 2D islands on top of the partially formed first Cd monolayer. Atomically resolved images of these islands have revealed an hexagonal atomic structure with an interatomic distance of 0.29 ± 0.01 nm. The dissolution of these features occurs together with the formation of many holes of monatomic height which induces a surface roughening. The alloy formation is explained considering a place exchange process between the Au atoms and the adsorbed Cd atoms followed by solid state diffusion of these atoms through the alloyed phase.

Molecular beam epitaxial growth of Cd1−yZnySexTe1−x on Si(211)

We report on the first successful growth of the quaternary alloy Cd1−yZnySexTe1−x(211) on 3-in. Si(211) substrates using molecular beam epitaxy (MBE). The growth of CdZnSeTe was performed using a compound CdTe effusion source, a compound ZnTe source, and an elemental Se effusion source. The alloy compositions (x and y) of the Cd1−yZnySexTe1−x quaternary compound were controlled through the Se/CdTe and ZnTe/CdTe flux ratios, respectively. Our results indicated that the surface morphology of CdZnSeTe improves as the Zn concentration decreases, which fits well with our previous observation that the surface morphology of CdZnTe/Si is poorer than that of CdSeTe/Si. Although the x-ray full-width at half-maximums (FWHMs) of CdZnSeTe/Si with 4% of Zn + Se remain relatively constant regardless of the individual Zn and Se concentrations, etched-pit density (EPD) measurements exhibit a higher dislocation count on CdZnSeTe/Si layers with about 2% Zn and Se incorporated. The enhancement of threading dislocations in these alloys might be due to an alloy disorder effect between ZnSe and CdTe phases. Our results indicate that the CdZnSeTe/Si quaternary material with low Zn or low Se concentration (less than 1.5%) while maintaining 4% total Zn + Se concentration can be used as lattice-matching composite substrates for long-wavelength infrared (LWIR) HgCdTe as an alternative for CdZnTe/Si or CdSeTe/Si.

The effect of rapid solidification on the structure, decomposition behavior, electrical and mechanical properties of the Sn–Cd binary alloys

A group of rapidly solidified Sn–Cd alloys has been prepared by a melt-spinning technique. X-ray diffraction, microstructure, and differential thermal analysis have been carried out. Young's modulus and internal friction have been measured, and the temperature dependence of resistivity has been evaluated. The results show a modification in both the microstructure and decomposition behavior. Also, an interesting connection between Young's modulus and the axial ratio (c/a) of the unit cell of the β-Sn was found in which Young's modulus increases by increasing the axial ratio (c/a). It was found also that the internal friction increases on increasing the Cd concentration.

Low temperature coefficient of resistivity Ag–Cd and Ag–Sn alloys—structure and transport

The microstructure vis-a-vis electrical transport behavior of Ag–Cd and Ag–Sn binary alloys in the temperature range 70–300 K has been studied. The 22.2 wt.% Cd and 29.4 wt.% Cd alloys were both found to have a single-phase structure made of solid solution of Ag. The lattice parameter however increased with increasing Cd content in the alloy. The microstructure of 17.7 wt.% Sn and 23.5 wt.% Sn alloys however is made of two phases Ag 4Sn and Ag 3Sn. The resistivity of Ag–Cd alloys increased with increasing Cd content and the temperature coefficient of resistivity (TCR) decreased to 1560 ppm K −1 for the 29.4 wt.% Cd alloy compared to 4100 ppm K −1 for pure Ag. The lowest TCR however was obtained for the 17.7 wt.% Sn alloy, 375 ppm K −1, which has a room temperature resistivity of 23.93 μΩ cm.

Serrated yielding in Cu-1 wt-%Cd alloy

The influence of grain size and temperature on the serration patterns of the Portevin-Le Chatelier (PLC) effect and on the yield and flow stresses in a Cu-1 wt-%Cd alloy was investigated in the temperature range 150 to 360 ° C. Two kinds of serration patterns were observed in this alloy. Type I occurred at lower temperatures and its yield points are moderately spaced. Type II consists of regular jerky flow observed athigher temperatures. The Hall-Petch equation is obeyed over the temperature range in which jerky flow occurs. The Hall-Petch parameter k (ϵ) is observed to show a local maximum in the temperature range where serrated flow is first observed. The PLC effect is associated with the solute- dislocation interactions, implying that k (ϵ) contains a component associated with grain size dependent dislocation storage.

Band Offset Dependence of Exciton Binding Energy in CdxZn1-xS/ZnS Quantum Wells

The enhancement of exciton binding energy was clearly observed with increasing cadmium (Cd) alloy content in CdxZn1-xS/ZnS quantum wells (QWs). However, the maximum exciton binding energy saturated at high Cd alloy content. The amount of decrease in exciton binding energy decreased with increasing Cd alloy content under an electric field.

Se, As, Mo, Ag, Cd, In, Sb, Pt, Au, Tl, Re traces in biogenic and abiogenic sulfides from Black Shales (Selwyn Basin, Yukon territories, Canada): A nuclear microprobe study

Black shales can be an important source of rare metals such as Cu, Ag, As, Mo, Se, Tl, Cd, platinum group elements (PGE) and gold (Pasava et al., Econ. Geol. 91 (1996) 63). However, especially in the case of noble metals, carriers such as discrete minerals could not be identified. This nuclear microprobe study brings new data on the partition of rare metals in Fe-, Fe (Ni)-, Ni- (Fe)-, Ni- and Zn-sulfides from the Ni-Zn-Mo-PGE mineralized marin black shales (Selwyn Basin, Yukon Territories). Sulfides are present as mineralized vestimentiferan tube-worms which are pyritized. Fluid-mineral interaction led to transformation of these biogenic Fe-sulfides successively to Fe–Ni- and Ni–Fe-sulfides which is indicated by increasing Se contents. Ni-sulfides which are interstital to the tube worms represent remobilized material, they are richest in Se. Several tens to thousands ppm of Cu, Zn, As, Se, Mo were located in the biomineralized and transformed tube worms. Antimony was located in Fe–Ni and Ni-, and Zn sulfides and Ag was present in Fe–Ni and Ni–Fe-sulfides. Pt and Au can also be related to submicron-sized inclusions in Fe–Ni sulfides. Hydrothermal fluids (at least 250 °C) precipitated silica around tube worms, intercalating submicron-sized sphalerites. Larger Zn-sulfides contain about 5000 ppm Cd and locally about 60 ppm In. Ba-rich K-feldspar contains Cl-rich Ag–Cd alloys.

Comparison of corrosion-resistance and hydrogen permeation properties of Zn–Ni, Zn–Ni–Cd and Cd coatings on low-carbon steel

Zn–Ni–Cd alloy was electroplated from an alkaline sulfate bath under potentiostatic conditions. The corrosion and hydrogen permeation characteristics of Zn–Ni–Cd alloy coatings electrodeposited from alkaline bath were studied and compared with those of Cd and Zn–Ni coatings obtained using commercial baths. Zn–Ni–Cd alloy was electroplated from an alkaline sulfate bath under potentiostatic conditions. The corrosion potential of this Zn–Ni–Cd coating was −0.62 V vs. SCE, which is still negative potential compared to iron. The corrosion rate of Zn–Ni–Cd coated steel was 0.073 mm y −1, which is estimated in a 0.5 M Na 2 SO 4+0.5 M H 3 BO 3 solution at a pH of 7. This value is much lower than the corrosion rate of Zn–Ni alloy (0.502 mm y −1) and Cd (0.306 mm y −1) coatings deposited from commercial baths. Zn–Ni–Cd alloys are also demonstrated to have superior hydrogen permeation inhibition properties compared to Cd and Zn–Ni coatings. Kinetic parameters of hydrogen permeation such as the transfer coefficient, α, the modified exchange current density, i 0 ′, thickness dependent adsorption–absorption rate constant, k ″, recombination rate constant, k 3, surface hydrogen coverage, θ s, were evaluated by applying a mathematical model to analyze experimental results.

Voltammetric Determination of Metals in Copper Alloys at Trace and Ultratrace Concentrations

The present work describes the analytical procedures for the voltammetric determination of Cu, Pb, Cd, Zn, Fe, Mn, Co, Ni, Sn, Sb and Bi in copper alloys. The possibility of determining simultaneously metal concentrations in the case of interference of the voltammetric signals due to the peak overlapping is also highlighted and discussed. The analytical procedure was verified by the analysis of the standard reference materials: commercial bronze A NIST-SRM 1115, gunmetal BCS-CRM 207/2, high tensile brass BCS-CRM 390. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were in all cases lower than 6%. The limits of detection for each element were also reported.

Kinetics of the low-temperature structural transformation in the In–4.3 at. % Cd solid solution

The reversible structural transformation of the hysteretic type observed previously by the authors in the In–4.3 at. %Cd alloy on low-temperature thermocycling is investigated further. In the hysteresis region (150–290 K) a pronounced instability of the macroscopic characteristics of the alloy is observed, which is manifested as time dependence of the dynamic Young’s modulus and resistivity of the samples at a constant temperature fixed during the cooling or heating run. The kinetic effects are investigated in detail near the boundaries of the hysteresis, where they are most clearly expressed. Less clear signs of the structural transformation are observed on the temperature dependence of the microhardness of the alloy. It is found that the structural transformation is governed by thermally activated processes with several characteristic relaxation times: the analytical form of the kinetic curves and the temperature dependence of the relaxation times are substantially different for the direct (on cooling) and reverse (on heating) transformations. Similarities and differences between this transformation and the known structural rearrangement processes in the physics of alloys are discussed. The structural transformation investigated here is also discussed in relation to the phase diagram of the In–Cd system.

Solvent extraction of metals with potassium-dihydro-bispyrazolyl-borate

The extraction of Cu(II), Ni(II), Co(II), Cd(II), Zn(II), Pb(II) and Mn(II) with potassium-dihydro-bispyrazolyl-borate (H 2BPz 2 −) in dichloromethane has been studied. Extraction constants (log K ex) have been calculated for all metal systems and were compared with those obtained with dibenzoylmethane (DBM), thenoyltrifluoroacetone (HTTA) and 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HPMBP). The method has been used for the determination of Cu(II), Co(II), Cd(II), Zn(II), Pb(II) and Mn(II) in standard alloys and for preconcentration of metal ions in synthetic samples.

Underpotential deposition of cadmium onto (111) face of silver from chloride containing solution

The underpotential deposition (UPD) of cadmium and Ag–Cd alloy formation on the (111) face of silver in chloride containing solutions were investigated by cyclic voltammetry and the potentiostatic pulse technique. It was shown that the UPD of cadmium commences at about −400 mV versus SCE (300 mV vs. Cd 2+/Cd) with the formation of ordered structure of the type ( 3 x 3 ) R30°. Chloride adatoms, which are adsorbed on the silver substrate when UPD of Cd starts, do not desorb. They become replaced by Cd adatoms and remain adsorbed and discharged on top of a Cd layer. At potentials close to the reversible potential of Cd alloying of Ag with Cd takes place, being expressed by two sharp cathodic peaks on the voltammograms.

Kinetics of martensitic transformation in Au–Cd alloys

Martensitic transformation temperatures, M s, M f, A s, and A f, of an annealed Au–47.5at.% Cd–0.75at.% Cu alloy were obtained by X-ray diffraction method and electrical resistivity measurement. It is confirmed that the four values obtained by these two methods are in good agreement within an experimental error. The incubation time for the low temperature phase was observed during the isothermal holding above M s, from the time dependence of Bragg intensity. The incubation time becomes shorter when the set temperature is close to M s.

Structure of nanometer-sized Au–Cd alloy particles near equiatomic compositions at room temperature

Nanometer (nm)-sized Au–Cd alloy particles with a composition of Au–44.6at.% Cd on average were prepared by a high vacuum electron beam deposition method, and their structure at room temperature was studied by lattice imaging and Fourier transform techniques in transmission electron microscopy, and electron diffraction. The Au–Cd alloy particles exhibited polyhedral shapes with facets, and possessed basically the B2 type structure similar to that of the β 2 phase Au–Cd alloys near equiatomic compositions in bulk. It was thus seen that the high temperature β 2 phase becomes stable in the nm-sized particles at room temperature. It was found, however, in some β 2 phase particles that modulated regions were formed a few nm in size with periods two and six times as large as the {110} planar spacing of the B2 lattice. The Fourier transform revealed that the modulated regions with twofold and six-fold periods have, respectively, definite crystal structures of the β 2′ and γ 2′ martensites in bulk. The modulated regions thus seemed to be the nuclei of these martensites. These martensite nuclei were coherent with each other and with the surrounding B2 matrix lattice. No clear interfaces between these martensites and the matrix were present, other than the common close-packed planes with which these martensites and the matrix are connected.

Effect of Cu and Zn on the melting and transformation temperatures of Pr and Gd

Phase equilibria in the R-rich regions of the R-Cu and R-Zn binary systems (R=Pr and Gd) have been investigated by differential thermal analysis, X-ray powder diffractometry, metallographic analysis and quantitative electron probe microanalysis. In these regions, the lowering (Δ T) of the melting and transformation temperatures of the rare earth metals by addition of copper and zinc resulted in eutectic and catatectic or eutectoidal type reactions. The Δ T observed in these systems are discussed and compared with those reported in the literature for the binary systems of Pr and Gd with Mg and with the elements from the 9th to the 14th group of the Periodic Table. In order to complete this systematics, a few Pr-rich Pr–Cd alloys have also been prepared and analysed.