Decomposition of silica binder during infiltration of Saffil fiber preform with Mg and Mg-Li melts

Mg and Mg-Li matrix composites were prepared by the melt infiltration of fibrous preform consisting of Saffil alumina fibers and the silica binder. During this process there has occurred decomposition of silica binder and/or surface silica film by displacement redox reactions and the reaction products were characterized using SEM, TEM, SAED, FTIR and XPS techniques. The only reaction products found in Mg infiltrated Saffil preform were MgO and Mg2Si. In Mg-Li melt infiltrated Saffil preform there was found besides MgO and Mg2Si also the non-crystalline phase that appears to be the lithium silicate xLi(2)O center dot ySiO(2). Binary lithium silicides and ternary magnesium-lithium silicides were not detected.