Magnesium and carbon materials are very good candidates for components for ultralight metal matrix composites, because of their low density and the very good mechanical properties of carbon reinforcement. [1][2][3][4] The use of carbon fibers in magnesium matrix composites is a common solution, however there are serious technologic problems both with ensuring a proper infiltration of the fiber roving or the fiber preform by the liquid metal and with obtaining products of various sizes and shapes. In some applications an alternative carbon material for reinforcement is glassy carbon particles (C p ) because the technologic problems typical for fibrous composites can be reduced by technologies typical for particles reinforced composites. The usability of glassy C p has been verified for polymer matrix composites [5] and aluminum matrix composites [6] and the results were very promising.In literature, magnesium alloys with aluminum have been proposed mainly for composite matrix use [1][2][3][4][7][8][9][10] because of their good technologic properties and the wide range of applications for magnesium cast products. The idea of using Mg-Al alloys as a matrix for composites reinforced with carbon fiber was also verified in literature. Formation of hydrophobic carbides with different intensities depending on the aluminum content in the magnesium alloy was observed at some conditions of consolidation [1][2][3][4]9] .In this article the results of preliminary works on a new material are shown. The aim of the presented experiment was to characterize the microstructure of a glassy C p /magnesium alloy (AZ91-Al 9 wt%, Zn 0.3 wt%) composite obtained by the powder metallurgy method, looking specifically at: -the possibility of the application of glassy C p instead of carbon fibers, and -the influence of the SiO 2 amorphous nanolayer deposited on the glassy C p surface on the composite microstructure.