The change in the composition of oxide layers and the possibility of the formation of bonding between the layers of a double oxide film defect when held in Al melts containing 0?7, 1 and 2 wt-%Mg were investigated. The defect was modelled by maintaining two aluminium oxide layers in contact with one another in the melt at 1023 K for times between 5 s and 50 h. Any changes in the composition and morphology of these layers were studied by SEM and energy dispersive X-ray. The results showed that in all the alloys, the initial Al 2 O 3 layer first transformed to MgAl 2 O 4 and then to MgO. These transformations caused the two layers to bond together gradually. The results confirmed that, in all the Al alloys containing 0?3-4?5 wt-%Mg, oxide films have the chance to heal if held in the liquid metal for a long enough period of time.

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