Corrosion Behavior of Electrolytic CoRe Alloys Under Exposure to an Alkaline Medium

Abstract

Corrosion behavior of electrolytic binary and ternary alloys in the 1 M KOH solution deposited from citrate-pyrophosphate electrolytes is studied. Based on the performed impedance measurements, the formation of a dense oxide layer which blocks the access of the electrolyte to the metal through cracks and pores is shown. Equivalent schemes have been selected and substantiated, and the parameters of the corrosion process have been calculated for 9 days of the samples exposure to the corrosive solution. Using chemical mapping it is shown that the corrosion product is predominantly cobalt oxide. A ternary alloy is characterized by a higher initial corrosion resistance of 6 kΩ×cm^–2 and a significant polarization resistance after slowing down and stabilization of the corrosion process – 37 kΩ×cm^–2.