The corrosion behavior of nanocrystalline nickel based thin films

In this study, the effect of Cr addition on corrosion behavior of Ni thin films were investigated. Ni thin films and Ni films with three different Cr content were deposited on glass substrates by magnetron sputtering. After deposition process, thin films with different Cr content were thermally treated in a rapid thermal process system. Phase analysis and grain size calculations of the samples were carried out by X-ray diffraction analysis. In order to reveal corrosion properties, potentiodynamic tests were conducted on samples. Analysis revealed that, although Cr addition to pure-Ni thin films improved their corrosion resistance, occurrence of σ-Cr₃Ni₂ phase at higher Cr contents increased corrosion rate. The corrosion properties of the samples were also investigated by electrochemical impedance spectroscopy and surface related parameters caused by corrosion reactions were calculated. The analysis revealed that at 55% wt. Cr, rapid ion exchange occurred and highest corrosion current, 23.4 nA cm⁻² was observed. - Highlights: • Thin film Ni–Cr samples were deposited on glass substrate. • Effect of Cr addition on corrosion behavior of Ni thin films were investigated. • Potentiodynamic tests and electrochemical impedance spectroscopy methods were used. • Cr content in Ni thin films plays and important role on corrosion. • Up to a certain Cr content, Cr addition reduces corrosion rate.