-Zinc electrowinning is performed with the application of a current through insoluble electrodes (Pb-Ag), causing the electrolysis of zinc sulfate, with or without impurities, and zinc deposition on the cathode of aluminum. The impurities can reduce the current efficiency and increase the energy consumption in zinc electrolysis. In this work, the effect of nickel and magnesium on zinc electrodeposition was studied using the electrochemical techniques of galvanostatic deposition and cyclic voltammetry. Additions of nickel, magnesium or both cations in zinc sulfate electrolyte resulted in a marginal increase in current efficiency. Addition of nickel or magnesium polarizes the cathode; however, the extent of polarization in the presence of magnesium is more than that of nickel. Addition of magnesium to the zinc electrolyte caused zinc reduction at a more negative potential. The addition of nickel to the zinc electrolyte increased the current density of the anodic peaks, thus increasing the dissolution of zinc and hydrogenated phases. The addition of nickel to the zinc and magnesium solutions decreased the nucleation loop, facilitating zinc deposition.
The ASME AS-240TP-316L stainless steel in the form of a sheet 3 mm in thickness and the ASTM SA-516 grade 60N steel substrate are joined by explosion cladding. The objective of this paper is to evaluate the electrochemical behaviour of a cladding plate of carbon-manganese steel and stainless steel 316L when compared to non-cladding plate 316L steel. The effect of the cladding process on the corrosion resistance was evaluated in a medium of aqueous solution of sulphuric acid. Anodic potentiodynamic polarisation curves were obtained to study the passivation behaviour of the cladding plate. Electrochemical impedance spectroscopy was performed to elucidate the corrosion mechanism of the cladding plate. The non-cladding ASME AS-240 TP-316L steel showed a higher corrosion potential, a lower passivation current density and a higher polarisation resistance, exhibiting a higher corrosion resistance than cladding 316L steel.
If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information.
About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation.
AbstractPurpose -The purpose of this paper is to study the corrosion of the coupling of two different types of stainless steel, austenitic and ferritic, used in the fabrication of water reservoirs in the solar energy industry. Design/methodology/approach -Potentiodynamic polarization and gravimetric immersion tests were used to evaluate corrosion of the coupling of two different types of stainless steel, austenitic and ferritic. Findings -The galvanic corrosion was not significant in the case of the coupling of AISI 304 and 444 steels. The difference of the open circuit potentials obtained for the AISI 304 and AISI 444 steels was 28 mV for the polished samples. The galvanic current density (i g ) was 55 nA/cm 2 . The corrosion observed in the stainless steel couple was in the weld area.Research limitations/implications -The methodology used is adequate to evaluate generalized galvanic corrosion. The problem of the corrosion in the coupling of the stainless steels is a problem of localized corrosion and the observed 28 mV potential difference was lower than the dispersion of results usually obtained from readings of corrosion potentials in electrochemical cells. Practical implications -The use of two different types of steel in contact with each other may lead to galvanic corrosion, and the welding of steel pieces may lead to several corrosion problems. Since the boiler may be used in different countries, subject to a great diversity of water quality, corrosion may be a significant problem. Originality/value -Literature data of the AISI 444 steel corrosion behaviour are still scarce. The coupling of two different stainless steels (AISI 304 and 444) in the water reservoir manufacturing was a necessary requirement of the solar energy industry. The manufacturers of boilers must evaluate and quantify the corrosion processes, which occur in the equipment used in the solar energy industry. As the solar energy industry has matured in the last ten years, the corrosion of this equipment may be a significant problem in due course.
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.