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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.

The magnesium alloy ZRE1 (2.7%Zn, 0.53%Zr, 3,14% rare earth elements) was applied as a matrix of composite reinforced with glassy carbon particles obtained by hot pressing of powder mixture. An influence of matrix chemical composition on interaction processes occurring at the interface was analyzed. The interface microstructure was characterized by scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). It was revealed the continuous bonding between components and a presence of zone enriched with zirconium, rare earth elements and oxygen in comparison to the matrix composition.

In the study the microstructure and tribological behavior of a new magnesium matrix composite reinforced with glassy carbon particles (GCp) were presented. In the composite, obtained by powder sintering, the magnesium alloy AZ91 was applied as a matrix with 20wt% of particles of diameter approx. 100 m. The particle-matrix bonding was characterized by SEM with EDS, TEM with SADP, and nanoidentation tests. The main interest focused on the influence of GCp on the wear behavior of the composite. In the experiment sliding velocities of 0.06, 0.09 and 0.14 m/s, and loads of 2.3, 5 and 9.3 N were applied. The glassy carbon particle microstructure after sliding and the debris were characterized with SEM and EDS. The sliding wear test revealed that glassy carbon particles decreased the coefficient of friction for low load and sliding velocity. The mass lost of composite was very low and no destructive processes of the steel counterface were observed. During the sliding process, a mixture of oxidized AZ91E alloy and dispersed glassy carbon is formed between the composite and the steel counter.