FEATURES OF THE FORMATION OF MICROSTRUCTURES IN METAL COATINGS DEPOSITED FROM VACUUM ARC PLASMA ON VARIOUS TYPES OF SUBSTRATES

Abstract

Transition metals and their alloys are widely used in chemical catalysis and successfully employed in electrochemical fuel cells, one of which is metal-air batteries (MABs). This study proposes the use of a high-entropy alloy (HEA) made of transition metals to create MAB electrodes. A cathode sample, a solid transition metal alloy of Fe-Co-Ni-Nb-Mo composition, was fabricated using low-temperature synthesis and plasma-sputtered using a VDU system. Continuous layers 94-103 μm thick and of stoichiometric composition identical to the sputtered cathode were deposited on copper substrates. The structure of the homogeneous coated layers, deposited by sputtering under medium vacuum conditions, contains microscopic inclusions with high oxygen and carbon contents. Circular depressions measuring 100-250 µm were found on the surface of sputtered cathodes. These depressions are related to the arc current on the surface, which is concentrated in the cathode spots. An increase in the energy performance of the MAB was demonstrated when testing HEA materials with plasma-treated surfaces as anodes. When treating an integral HEA cathode, a rough relief is formed on its surface, which reduces the current density and improves the chemical resistance of the material