Spectrophotometric Monitoring of Chloride Electrolyte for the Electrochemical Deposition of Permalloy

The use of chloride electrolytes for the electrochemical deposition of the Ni81Fe19 permalloy is promising because sulfate electrolytes are unstable in the presence of sulfur. The magnetic properties of the Ni81Fe19 alloy are very sensitive to the deviation of the composition from the molar ratio of 4.26 between components. In this study, the accuracy of preparing the chloride electrolyte for the electrochemical deposition of a permalloy is controlled using spectrophotometry. Analysis of the spectra of light absorption and scattering by the iron hydroxide colloidal species of the electrolyte reveals that the electrolytic dissociation of bivalent iron and the mechanism of anomalous nickel and iron codeposition depend on the temperature and affect the electrochemical deposition of permalloy films. It is noted that the precipitation of ferrous hydroxide in the form of a colloidal species with boric acid as a complexing agent is a specific feature of ferrous chloride during hydrolysis. It is shown that, after filtrating iron chloride solution, nickel is precipitated from the chloride electrolyte better than iron. It is established that the normal congruent deposition of Ni81Fe19 alloy films takes place and abnormal codeposition is excluded.