Study Of Copper Deposition Research Articles

ToF-secondary ion mass-spectrometric study of copper deposition and stripping on directly heated screen-printed gold electrodes

We report about a new kind of directly heated gold electrode. All electrodes including a directly heated gold loop electrode, a Ag pseudo reference, and a carbon counter electrode have been screen-printed on a ceramic alumina substrate. Thermal behaviour was studied by potentiometry using either an external or the integrated reference electrode. Stripping voltammetric copper signals were greatly improved at elevated deposition temperature. Secondary ion mass spectrometric studies (ToF-SIMS) revealed that different negative ionic species of copper complexes can be found on the gold electrode surface as a result of ion bombardment during SIMS analysis like Cu−, CuCl− and CuCl2 −. SIMS surface imaging using a fine focussed ion beam over the surface allowed us to obtain ion images (chemical maps) of the analyzed sample. SIMS depth profile analysis of the gold loop electrode was performed after copper deposition at room temperature (23 °C) and at 60 °C. CuCl2 − ion was used for the depth profile studies as it has shown the highest intensity among other observed species. Surface spectroscopic analysis, surface imaging and depth profile analysis have shown that the amount of deposited copper species on the gold loop electrode was increased upon increasing electrode temperature during the deposition step. Therefore, the presence of chloride in the solution will hinder underpotential deposition of Cu(0) and lead to badly defined and resolved stripping peaks.

Kinetic Study of Copper Deposition on Zinc by Cementation Reaction and Effects of Some Amino Acids

Kinetic Study of Copper Deposition on Zinc by Cementation Reaction and Effects of Some Amino Acids

Electrochemical modeling and study of copper deposition from concentrated ammoniacal sulfate solutions

A fundamental investigation of the electrolytic deposition of copper from concentrated aqueous ammoniacal solutions has been carried out based on the thermodynamic analysis of the system Cu–NH 3–H 2O. The speciation of copper vs. pH and redox potential was modeled in high ionic strength solutions, in which the activity coefficients of the system species were estimated according to the Modified Bromley's Methodology. The electrochemical behavior of the redox system Cu(0)/Cu(I)/Cu(II) in concentrated aqueous ammoniacal solutions was studied at pH = 9.5 and the cathodic reactions in these solutions were determined. It was found that metallic copper was formed under strongly reductive redox conditions, while under mildly reductive to mildly oxidative conditions the cuprous di-ammine complex species dominate. Under highly oxidative conditions the cupric tetra-ammine complex species predominated. According to the theory and results, the cathodic deposition of copper from concentrated aqueous ammoniacal solutions proceeds in a two-step reduction mechanism. The cupric ammine species are first reduced to cuprous di-ammine, which in turn is reduced to metallic copper. The electrochemical experiments revealed that copper deposition over time follows a sigmoid-type curve, verifying the two-step mechanism. The main feature of these sigmoid curves was the presence of an induction period with negligible copper deposition, followed by an acceleration period where the copper deposition rate gradually increased. By increasing the applied cell voltage, the induction period was significantly reduced or disappeared.

A study of copper deposition in the presence of Group-15 elements by cyclic voltammetry and Auger-electron spectroscopy

The behaviour of arsenic, antimony, and bismuth during electrolytic refining of copper has been investigated using cyclic voltammetry, scanning electron microscopy, X-ray diffraction analysis and Auger electron spectroscopy. Electrodeposition was conducted using Group 15 element additions to two different cupric sulfate electrolytes: commercial tank house electrolytes containing 45 g l−1 Cu2+ and 200 g l−1 H2SO4 and liberator cell conditions containing 10 g l−1 Cu2+ and 400 g l−1 H2SO4. Analysis of electrochemical kinetic parameters indicates that the copper cathodes were more active at the higher sulfuric acid concentrations. SEM analysis revealed that Sb and Bi additions promoted truncated copper crystals while As-containing electrolytes produced random crystals. XRD patterns indicated Group 15 elements favour the production of (2 2 0) crystallographic orientation. Surface analyses of the copper deposits using AES techniques show that arsenic and antimony are deposited electrochemically forming primarily solid solution phases with copper in commercial tank house electrolytes. Under liberator cell conditions, a Cu3As intermetallic phase forms when arsenic is present in the electrolyte. Antimony is present in solid solution under these conditions. Reduction of bismuth was not detected during these experiments.

A parametric study of copper deposition in a fluidized bed electrode

The behaviour of a fluidized bed electrode of copper particles in an electrolyte of deoxygenated 5×10−1 mol dm−3Na2SO4−10−3mol dm−3H2SO4 containing low levels of Cu(II), is described as a function of applied potential, bed depth, flow rate, particle size range, Cu(II) concentration and temperature. The observed (cross sectional) current densities were more than two orders of magnitude greater than in the absence of the bed, and current efficiencies for copper deposition were typically 99%.

A study of copper deposition in rectified half-wave potential-train electrolysis

The deposition of copper from acidified sulphate solutions via rectified sinusoidal half-wave potential-train electrolysis, at various magnetic flux densities is analyzed in terms of asymptotic tendencies observed in associated current—cell potential drop graphs. In proper combinations of frequency and magnetic field strength, good-quality deposits can be obtained up to current densities of 1400 A m −2.