In the present study, the wear behavior of in situ formed Al2O3 reinforced hypereutectic Al-18Si matrix composite coatings have been investigated. These coatings were successfully fabricated with mechanically alloyed Al-12Si and SiO2 powder deposited on aluminum substrates by atmospheric plasma spraying (APS). The produced samples were characterized by means of microscopic examinations, hardness measurements and wear tests. The obtained results pointed out that the amount of in situ formed Al2O3 particles increased with increasing spray distance and decreasing in-flight particle velocity and temperature, which was accompanied by an improvement in hardness and wear resistance. (C) 2009 Elsevier Ltd. All rights reserved.