Optimum Electrolyte Composition Research Articles

Effect of electrolyte composition on the conditions of formation of a finely divided tin-bismuth alloy

1. It is shown that raising the electrolyte concentration increases the rate of tin and bismuth ion discharge, and at the same time improves the alloy current efficiency. 2. It has been established that raising the concentration of hydrochloric acid in the electrolyte brings about a decrease in alloy current efficiency, which is a result of an increase in the amount of hydrogen being liberated. 3. With rising concentration of the complex-forming agent the alloy and bismuth current efficiencies grow as a consequence of Increase in the rate of [BiCl4]−ion discharge. 4. The optimum electrolyte composition and process parameters, ensuring the formation of an alloy with 38% tin and 47% bismuth, are:CSnCl2 50 g/liter,CBiCl3 50 g/liter,CNH4Cl 100 g/liter,CHCl 20 g/liter, lc=15 A/dm2, T=20°C, and 0.5% solution of oleic acid in toluene as the upper layer.

Precipitation of fine bismuth powders on passivated electrodes

1. A study was made of the conditions of electrodeposition of finely divided bismuth in a two-layer bath whose organic layer is a solution of oleic acid in toluene. It was established that the necessary condition for the production of fine powders by this method is the addition to the electrolyte of NH4C1, which decreases the hydrolysis of bismuth chloride and increases its solubility. 2. The optimum electrolyte composition and process parameters for the production of fine bismuth powders were found to be as follows:\(C_{BiCl_3 .2H_2 O} \)= 100 g/liter, CHC1=20 g/liter,\(C_{NH_4 Cl} \)=150 g/liter, ic = 30–40 A/dm2, t = 15–20°C, Vrev=60 rpm, and CSAA (surface active agent) = 0.5% solution of oleic acid in toluene.

An investigation into the recovery of zinc from zinc chloride-sodium chloride mixtures by electrolysis

The electrolysis of zinc chloride-sodium chloride mixtures to yield zinc and chlorine has been examined. The optimum electrolyte composition was found to extend from 75% to 60% zinc chloride. In order to obtain the maximum current and energy efficiencies, it was found necessary to use horizontal electrodes with perforations to allow easy escape of the electrolysis products.

Anodic oxidation as sectioning technique for the analysis of impurity concentration profiles in silicon

Abstract Anodic oxidation is a commonly used technique for impurity profile determination in silicon. Optimum electrolyte composition, anodization conditions and problems involved in the determination of silicon removed by anodization are examined together with effects due to sample preparation and silicon characteristics. Experimental data are presented for the use of the ethylene glycol electrolyte together with the limits of accuracy of the technique. The use of the ellipsometric method in the evaluation of refractive index and thickness of silicon anodic oxides is illustrated and discussed.

Electrodeposition of nickel ? Iron alloy powder

1. On the basis of an investigation into the properties of various solutions, the following optimum electrolyte composition (moles/liter) was chosen: 0.2 nickel and iron (jointly) in the form of sulfates, 0.38 (NH4)2SO4, 0.07 NaF, and 0.2 KCl; pH 5. 2. It is shown that the composition of the iron-nickel alloy powder is governed by the concentration of its components in the electrolyte, but is not affected by changes in current density or electrolyte temperature. These characteristics are attributed to the fact that the limiting discharge currents of nickel and iron are similar and change in an equivalent manner under the influence of electrolysis conditions. 3. A study was made of the phase composition of the alloy as a function of nickel and iron concentrations and current density. It was established that the alloys represent a continuous series of solid solutions. 4. The influence of electrolyte composition and electrolysis parameters on the current efficiency was investigated. It was concluded that the optimum electrolysis parameters are a current density of 3000 A/m2 and a temperature of 30°C. 5. The physical properties of the alloy powders were investigated as a function of electrolysis conditions. It was found that 54% of all particles in the powder produced under the optimum conditions are <42μ in size, and have an apparent density of 2.85–3.0 g/cm3 and a specific surface area of 1.84×10−2 m2/g. The current efficiency under such conditions is 72–74%.