During the hydrometallurgical processing of nickel from raw materials, the leach liquors are found to be contaminated with several impurities. These impurities in the electrolytic cell affect the deposition characteristics as well as the kinetics and mechanism of nickel electrodeposition process resulting in lower current efficiency (CE) and poor nickel deposits. In order to improve the quality of the nickel deposits, it is imperative to use organic additives in the nickel plating bath to improve the structural, mechanical, and morphological properties of the deposits. Furthermore, it is usually observed that in spite of various purification techniques like cementation and solvent extraction, metals obtained at the cathode are usually contaminated with inorganic impurities. This review thus presents a comprehensive overview of some important studies and investigations performed on various inorganic and organic additives employed in nickel electrodeposition processes from various baths such as Watts, sulfate, acetate, formamide, lactate, and baths containing ionic liquids. The presence of metallic (inorganic) impurities in industrial electrolytes is very common. Most of these impurities affect the deposit’s characteristics, CE, deposition overvoltage, and cathode purity. Addition of inorganic cations such as Al3+, Mg2+, Mn2+, and Zn2+ did not have a significant effect on the CE; nevertheless, the physical appearance and crystallographic orientation of nickel deposits were significantly affected. Organic additives are usually added to the nickel electrolytic bath to counter the harmful effects of these metallic impurities entrained in the bath, where they also affect the growth and crystal building of the deposits through their adsorption onto the cathode surface. Most of these additives act as hydrogen inhibitors, crystal growth modifiers, brighteners, levelers, wetting agents, and stress reducers, and hence, their appropriate addition was important for the formation of fine-grained, smooth, and compact deposits. This review demonstrates that the quality of the nickel deposit was strongly affected if the concentration of the inorganic impurity in the nickel bath exceeded the tolerance limit. From this review article, the roles of various organic additives as a brightener, leveler, and antipitting agent, etc. in the Ni plating bath could be established, and these additives would play a significant role in the formation of bright, smooth, and coherent nickel deposits obtained during hydrometallurgical processing of laterite and sulfide ores in the metallurgical industry.

Roles of organic and inorganic additives on the surface quality, morphology, and polarization behavior during nickel electrodeposition from various baths: a review

Electrodeposition of nickel–phosphorus from a highly conductive citrate bath for wire bonding applications

Direct and pulsed current electrodeposition of Zn-Mn coatings from additive-free chloride electrolytes for improved corrosion resistance

Thermal conductivity and thermal diffusivity of porous rocks have been measured simultaneously by Gustafsson probe in the temperature range of 280-330 K at normal pressure using air as the saturant. Data are presented for five types of samples ranging in porosity from 8 to 17%, and to show the variation of thermal conductivity with porosity. An empirical formula is suggested to account for the estimation of thermal conductivity of porous sandstones in terms of porosity and thermal conductivities of the mineral constituents. Thermal conductivities of the samples do not change much within the temperature of measurement.

Thermophysical Properties of Porous Media: Consolidated Sandstones

Nickel is usually electrodeposited from the Watts bath. Other baths like sulphamate and fluoborate are also of industrial importance but are used less commonly. Perchlorate solutions, though examin...

Electrodeposition of Nickel from Perchlorate Based Electrolytes

Electrodeposition of nickel is largely carried out as an undercoat in decorative nickel-chromium plating. During the process of nickel plating, the solution pH tends to rise because of depletion of hydrogen ions due to hydrogen evolution from the layer of solution surrounding the cathode. It thus becomes necessary to maintain the pH of the plating solution within the appropriate range for ensuring production of deposits with desirable properties. In this paper the authors report the effects of certain buffering ingredients, namely acetate, citrate, succinate and tartrate salts in nickel plating solutions. The experimental results point to the suitability of acetate as a superior buffering agent for a nickel plating bath

Effect of organic acids in nickel plating

Chromium plating finds not only decorative but also functional applications. Generally chromium deposits are obtained from electrolytes with an approximate ratio of 100:1 of chromic acid to sulphuric acid. The Self Regulating High Speed (SRHS) chromium plating electrolytes, which are often employed for hard chromium plating though of higher efficiency have the disadvantages of cathodic etching and higher corrosivity. These are mainly due to the presence of a fluorine compound as a bath constituent. In this paper we report the results of experiments carried out with nonetching electrolytes but containing sulphate and potassium iodate. Different concentrations of chromic acid, sulphate and potassium iodate were used and current efficiency, rate of build-up, throwing power, deposit nature and microhardness were evaluated

A. Aruna

Papers

Effect of organic acids in nickel plating

Influence of potassium iodate on chromium deposition