Investigation of the Characteristics of MAO Coatings Formed on Ti6Al4V Titanium Alloy in Electrolytes with Graphene Oxide Additives
Sergey N. Grigoriev, Nikita Peretyagin, A. V. Apelfeld, Antón Smirnov, A. A. Rybkina, Ekaterina Kameneva, Artem Zheltukhin, М. В. Герасимов, М. A. Volosova, O. O. Yanushevich, Нателла Крихели, Pavel Peretyagin
Abstract
Coatings with a thickness from ~40 to ~50 µm on Ti6Al4V titanium alloy were formed by micro-arc oxidation in a silicate-hypophosphite electrolyte with additions of graphene oxide. Micro-arc oxidation treatment was carried out in the anode–cathode mode (50 Hz) with a ratio of anode to cathode currents of 1:1, a total density of 20 A/dm2, and a treatment duration of 30 min. The effect of the graphene oxide concentration in electrolytes on the thickness, roughness, hardness, surface morphology, structure, composition of micro-arc oxidation coatings, and its electrochemical corrosion behavior in 3.5% NaCl solution was studied. The input of graphene oxide additives into the base silicate hypophosphite electrolyte led to an increase in the hardness of micro-arc oxidation coatings. Electrochemical polarization studies and impedance data showed that the best characteristics in terms of corrosion-protective ability among coatings formed in electrolytes with graphene oxide additives were those formed in the electrolyte with a graphene oxide concentration of 0.1 g·L−l. A further increase in the graphene oxide concentration in the electrolyte did not improve the protective properties of micro-arc oxidation coatings.