Abstract <p>A corrosion behavior of an intermetallic compound and solid solutions based on the Co75Me25 two-component systems, where Me = Si, Fe, Cr, is considered. The surface morphology of the samples is analyzed using electron and optical microscopy. Corrosion is studied using the polarization-curve method and electrochemical impedance spectroscopy. The greatest corrosion resistance is shown to be achieved in the Co–Cr sample due to the presence of chromium alloying additive, an inhibitory component. Results of corrosion tests for the catalytic capabilities of two-component alloys is discussed briefly. This study also made it possible to explain the role of the intermetallic compound Co₂Si in terms of corrosion behavior of an active electrode-catalyst in the nitrate electrochemical reduction reaction.</p>