Microstructure and mechanical properties evaluation of molybdenum disulfide-titania nanocomposite coatings grown by plasma electrolytic oxidation

In this work, the molybdenum disulfide-titania (MoS2-TiO2) nanocomposite oxide coating on Ti-6A1-4V alloy was fabricated by plasma electrolytic oxidation (PEO) process. The MoS2 particles with concentrations of 4 g/L was added into the electrolyte and three duty cycle values, 20%, 35% and 50% at a fixed frequency of 1000 Hz were used. We found that shorter activation time and lower breakdown voltage for the PEO reaction was achieved due to the addition of 4 g/L MoS2 particles in the electrolyte. The oxygen rich, rutile and anatase nonstoichiometric TiO2 phases were produced for all oxide coatings. In this work, the one-step PEO grown coatings consisting of MoS2-TiO2 nanocomposite structure with good adhesion, low coefficient of friction and low wear rate were achieved due to the lubricious effect of the 4 g/L MoS2 particles in electrolyte under a duty cycle of 50%. (C) 2016 Elsevier B.V. All rights reserved.