Different post treatment methods are developed up to now to improve the properties of thermally sprayed coatings. In this work, arc sprayed aluminium coatings on aluminium substrates are post-treated by plasma electrolytic oxidation. To estimate the wear resistance of resulting oxide coatings, two abrasive wear tests (ASTM G65 and ASTM C1624) are carried out. Worn surfaces are examined by scanning electron microscopy in order to establish the wear mechanisms. These results of the abrasive wear tests are correlated with the parameters of the PEO process and the hence resulting micro structures of the coatings.