In this study, thick ceramic coatings were fabricated by microarc oxidation on 7075 aluminum alloy in a KOH, Na(2)SiO(3) solution. Micro arc oxidation was performed by using an AC power supply operating in variable frequency 100 Hz between 160 Hz. Mechanical and physical properties were examined on the surface of the oxide film including hardness, wear resistance and surface roughness. Rockwell C testing was used to compare the relative adhesion characteristics of the oxide film. The surface morphology and structure was examined by SEM and X-ray diffractometer. The studied properties of the samples as a function of frequency were discussed.