Micro-structures and growth mechanisms of plasma electrolytic oxidation coatings on aluminium at different current densities

In this study, plasma electrolytic oxidation (PEO) coatings were produced on pure aluminum in an in-house developed composite electrolyte at three current densities of 2.2 A/dm2, 4.4 A/dm2 and 8.8 A/dm2, respectively. The coatings were investigated based on the observation and measurement of the working voltage, surface microdischarges and morphologies of surface, polished cross-section, fracture cross-section and inner surface of the coatings,...