Selected problems in the continuous electrodeposition of Ni-Fe alloys

Abstract

Electrochemical ferrous metal alloy films (Ni-Fe, Ni-Fe-Co etc.) deposited on cylindrical wires are used for the production of memory elements in third generation computers. As the technology of the production of such information carriers is based on several electrochemical processes, knowledge of the electrode processes is essential. The nickel and Ni-Fe alloy deposition processes on cylindrical electrodes from sulphate-chloride solution with additives such as boric acid, saccharin, sodium lauryl sulphate were investigated. It was established that the nickel deposition rate was controlled by the ion discharge whereas the iron deposition was controlled by the transport of ferrous ions to the electrolyte layer near the cathode. The current efficiency of the cathode process amounted to 60–90%. Hydrogen evolution was controlled by the diffusion of proton source molecules. The alloy film composition and the current efficiencies depended strongly on the solution composition and to a lesser extent on other electrolysis parameters (current density, temperature, solution circulation etc.).