Inherited chemical inhomogeneity in oxide layers deposited by the method of microarc oxidizing on hypereutectic silumins

The effect of the size and of the kind of distribution of silicon in Al-Si alloys with hypereutectic composition on the characteristics of the oxide layer formed by microarc oxidizing (MAO) is studied. It is shown that the inhomogeneity of the distribution of silicon in the oxide layers is inherited from the initial structure of the alloys. The mechanism of the effect of silicon on the structure of oxide layers and the processes of their formation due to MAO of hypereutectic silumins are discussed. It is shown that it is principally possible to use the method of microarc oxidizing for obtaining hardened layers with controlled distribution of silicon. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 23–27, March, 2007.