port conditions on the reaction surface and helped smooth the deposit at the expense of the current efficiency. As the hydrogen evolution reaction dominates over 90% of the process, the alloy deposit loses its integrity. Note in Fig. 14g for the Cu-5 bath at -1.6V, segregated areas of copperrich and nickel-rich can be seen as well as numerous cracks caused by hydrogen embrittlement. ConclusionsCodeposition of copper-nickel alloys occurs in a fairly narrow potential region, namely, between -1.0 to -1.2V vs. SCE. In this region, a wide variety of alloy composition (0-50% nickel) and fairly smooth deposits can be obtained. Because copper deposition is near mass transport limited in the codeposition region, it is important that the plating bath is well-agitated. The composition of the alloy deposit can be controlled by the molar metal ion ratio in solution as well as the electrode potential. If greater operational control is needed, alternative plating schemes such as pulse plating can be utilized. Preliminary pulse-potential deposition of this alloy produced some improved surface morphology as well as greater compositional control. Also, for greater applicability, it is useful to model the alloy dep~ osition process as discussed in part II of this paper (18).
An engineering analysis was carried out on a packed-bed electrochemical reactor in Which the electrolyte flowed in the axial direction and current flowed in the radial direction. Experimental measurements with a sectioned porous electrode were conducted to measure the axial current distribution both at and below the limiting current. The experiments involved deposition of copper onto stacks of copper screens with acidified copper sulfate electrolyte. Although the presence of flow channeling caused the mass transfer coefficient to be less than the value reported in the literature, an empirical correlation was established for estimating the mass transfer coefficient. The reactor system gave polarization curves which indicated that the exchange current density was 0.067 mA/cm 2 in 0.001M CuSO4 + 1.5M H2SO4. Comparison between axial current distribution data and theory was made with respect to collection efficiency, axial current distribution, electrode polarization, and total current. Agreement was found for a range of reactors having various geometric dimensions, porosities, flow rates, and reactant concentrations. The theory was used to generate criteria for estimating the volumetric reaction rate, as well as for estimating conditions under which the perpendicular configuration reactor gives higher volumetric reaction rates than when the current and electrolyte flow in parallel directions.
An analysis is presented for describing behavior of a packed‐bed electrode confined within a thin cylindrical porous separator and surrounded by a concentric counterelectrode. Electrolytic solution, containing reactive species, flows axially in plug flow through the packed‐bed electrode while the peripheral surface of the packed bed is held under a constant applied potential. Results are obtained for two types of porous separators, (i) permeable to all solute species and (ii) impermeable to the reactive solute species. For each case, the two‐dimensional (radial and axial) concentration, potential, and current distributions are calculated by a finite difference method. The results clarify over‐all reactor performance and, in particular, predict the relation between the volumetric reaction rate and the residence time for a wide range of system parameters.
There is a need for reliable models of the mass transfer characteristics of hollow tube Donnan dialyzers, to guide application to industrially significant problems such as recovery from electroplating waste water. This work is focused on determining mass transport correlations in a shell-and-tube dialyzer, fabricated from ion-selective membranes, used to extract nickel from dilute nickel sulfate solution with sulfuric acid as the stripping agent. Correlations between mass transport coefficient and Reynolds number are reported for both laminar and turbulent flow regimes. , Electrochemieal Society Active Member. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.122.253.212 Downloaded on 2015-05-15 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.122.253.212 Downloaded on 2015-05-15 to IP ABSTRACTThe electrochemical and photoelectrochemical properties of single crystal n-type In203 were examined in 1M NaOI-I and 1N H2SO4. The photocurrentwavelength response indicated the absorption edge is an indirect transition of about 2.3-2.5 eV. The flatband potentials were determined from Mott-Schottky * Electrochemical Society Active Member.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.