Physical properties of formal oxide layer on aluminum substrate by plasma electrolysis oxidation in alkali solutions using unipolar current system and the physical properties of the oxide film generated

Oxide layers produced by plasma electrolysis oxidation are nowadays receiving considerable attention because of their useful characteristics. The high-temperature ceramic layers thus produced enjoy such properties as high hardness and wear resistance among others. They include α-Al2O3 and γ- Al2O3 phases and their porosity is much lower than that of the conventionally produced ceramic layers. There is a variety of current regimes applied with important effects on their properties. This study investigates the production of hard ceramic layers on aluminum using direct pulsed current in plasma electrolysis oxidation. The results reveal that, compared with the direct current method, the pulsed current improves the characteristics of the PEO coatings due to its better control over the coating mechanism.