Ceramic matrix composite production by directed melt oxidation of pure aluminium metal using spinel dopants

Abstract

The production of Al₂O₃ matrix composites by directed melt oxidation of pure Al externally doped with spinel type dopants has been investigated. The presence of any one of MgAl₂O₄ , LiAlO₂, and ZnAl₂O₄ resulted in oxide growths in a similar fashion to the growths produced using elemental Mg, Li, and Zn. Rapid growth was achieved at 1180°C with MgAl₂O₄ and at 900°C with LiAlO₂ . The growth rates at 1180°C of the samples doped with ZnAl₂O₄ were less rapid than the growth rates of the samples doped with MgAl₂O₄ . The fact that growth is initiated by mixed oxide spinel dopants is further evidence in support of the cyclic reaction sequences that have been proposed for directed melt oxidation.