Effect of Surface Microstructure on the Corrosion Resistance and Magnetic Properties of an Amorphous Cobalt-Based Co–Si–Fe–Cr–Al Alloy

The surface of an amorphous cobalt-based alloy with a nominal composition of Co75Si15Fe5Cr4.5Al0.5 was modified with nanostructures by anodizing in an ionic liquid—1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. The magnetic (specific saturation magnetization and coercive force) and corrosion (corrosion potential and resistance) characteristics of an amorphous alloy before and after electrochemical modification of the surface with nanostructures have been compared. Modification of the alloy surface partially changes its magnetic properties. After corrosion tests, an increase in the coercive force is observed. Corrosion tests were carried out using the polarization curve method in Ringer’s solution. The corrosion resistance of alloys modified with oxide nanostructures is higher than the corrosion resistance of an abrasive-treated alloy. The increase in corrosion resistance is determined mainly by the presence of nanostructures.