Electrodeposition Of Binary Alloys Research Articles

Exploiting Phase Separation in Electrodeposition of Binary Alloys

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The Role of Homogeneous Chemical Kinetics in the Anomalous Codeposition of Binary Alloys

The role of finite-rate homogeneous chemistry during the electrodeposition of binary alloys is analyzed using a detailed mathematical model. The model accounts for solute reactions and transport within the aqueous boundary layer as well as multistep reactions on the electrode surface. Calculations are carried out for nickel-iron deposition from a sulfate bath, using a previously proposed surface-reaction mechanism that accounts for the observed anomalous codeposition. The common assumption of homogeneous chemical equilibrium is found to produce only modest errors in the computed deposition rates, but it distorts the relative importance of hydrolyzed metal ions. In contrast with previous literature claims, the present calculations show that these ions tend to have a greater role than is predicted by assuming equilibrium. The model also suggests that the precipitation of solid metal hydroxides may be slow, i.e., that substantial supersaturation of the plating solution may occur.

Electrodeposition of Alloys with Composition Modulated over Their Thickness: A Review

Calculations of near-electrode concentrations of reactant ions and their variations with time during electrodeposition of binary alloys with a modulated-over-thickness composition are presented for various types of pulsed electrolysis. Thicknesses of pure components and alloys of variable compositions at various ratios between component concentrations and pulse magnitudes are established. The role played by exaltation effects, alloying, crystallization factors, and dissolution of the electronegative component from the alloy in a next pulse is shown.

Electrodeposition of composition‐modulated alloys in a fluctuating flow field

AbstractThe effect of fluctuating flow on the electrodeposition of binary alloys is analyzed by numerically solving the transient Navier‐Stokes and species continuity equations for a rotating disk electrode system. Timeperiodic modulations of the flow field and the electrode potential are studied and shown to induce periodic deposition rates for a mass‐transfer‐limited species and an activation‐limited species, respectively. Dimensionless groups are formulated to characterize the operating regimes, where composition‐modulated alloys electrodeposit from a single electrolyte and where fluctuating flow influences the composition distribution of the deposit. It is shown that changing the phase angle difference between the flow and potential modulation waveforms can modify the composition gradients in the deposited alloy, whereas other features of the alloy, such as the total composition variation, are affected less by fluctuating flow.

Electrodeposition of binary alloys: an account of recent developments

Recent literature on the electrodeposition of binary alloys is critically reviewed. Activity in.alloy deposition from aqueous media has shown a continuing expansion in recent years. Alloy plating for protective and decorative purposes continues to be prominent. The principal newer areas of interest for practical usage are magnetic alloys for various applications in computer technology, from electroforming diverse articles for intricate electronics hardware to large parts for use in aircraft and aerospace industries and for electroplating on plastics. In addition to the plating of alloys from aqueous solutions, the binary alloys plated from fused salt electrolytes are also mentioned. It is apparent that alloy plating will continue to fill a need in technology for special items which cannot be produced in any other way.