The introduction of scandium into quasicrystalline Al–Cu–Fe films obtained by vacuum evaporation has a significant effect on their structure and corrosion resistance. The addition of scandium promotes the formation of a finer and more homogeneous nanostructure, which is confirmed by X-ray diffraction and atomic force microscopy data.
Quasicrystalline Al–Cu–Fe and Al–Cu–Fe–Sc films with thicknesses ranging from 200 to 260 nm were investigated for their structure and corrosion resistance. The films were produced by three-electrode ion-plasma sputtering of specially prepared targets.
To determine the structure and phase composition of the films, transmission and scanning electron microscopy, X-ray diffraction and electron probe analysis were used. The corrosion behavior was studied in aqueous solutions of NaCl with concentrations of 3, 5 and 16%, having a pH of 6.9, at room temperature.
The formation of a fine-grained icosahedral quasi-crystalline phase in the deposited films was established. The nanostructure of the coatings is confirmed by the sizes of the coherent scattering regions. The introduction of 0.5 at.% Sc into the quasi-crystalline Al–Cu–Fe films improves their anti-corrosion characteristics, which is confirmed by measurements of stationary potentials in salt solutions of different concentrations.
Improved structure, in turn, has a positive effect on the corrosion properties of films. Electrochemical measurements have shown that scandium reduces the corrosion rate in aggressive environments, such as chloride solutions. This is due to the formation of a protective oxide layer on the film surface, enriched with scandium, which prevents the penetration of corrosive ions.
Thus, scandium doping is an effective way to modify the structure and increase the corrosion resistance of quasicrystalline Al–Cu–Fe films, which opens up prospects for their application in various fields, including protective coatings and sensors.
Author:S.I. Ryabtsev, V.A. Polonsky, O.V. Sukhova
Institute:Oles Honchar Dnipro National University; National Academy of Sciences of Ukraine