MAB phase-alumina composite formation via aluminothermic exchange reactions

Abstract

The formation of MAB phase-alumina composites through aluminothermic exchange reactions using M-element (Fe, Mn, Cr, Mo, W) oxides has been investigated for the MAB phases Fe2AlB2, Mn2AlB2, Cr2AlB2, MoAlB, and WAlB for the first time. With the exception of WAlB, all systems formed MAB phase and alumina as major phases, with binary M-element borides, aluminides and/or oxides as minor phases. An alternative Al ratio (120%) was investigated, which increased conversion to all MAB phases except Fe2AlB2. Exchange reactions using oxides present a potential alternative to synthesis methods using often more expensive pure elements.