Some results of the studies where the interface between the Mg alloy matrix or the ceramic reinforcements have been characterized by carrying out experiments to measure dynamic wettability, wear properties and coefficient of thermal expansion in infiltrated composites are presented. The tribological studies and dispersion as well as microhardness measurements show that by coating the particles and by varying the interface characteristic by changing the preheat temperature of the preform, the microhardness values and the tribological properties are altered due to change in wettability. Results of the studies done on measurement of the coefficient of thermal expansion of Mg alloys reinforced with hybrid type of reinforcement consisting of SiC_p, C-fibers and Mg₂Si in-situ generated particles show that the thermal cycling initially leads to rapid linear expansion of the composite. However, the expansion gets stabilised after a few cycles, perhaps, pointing to the formation of more stable interfaces.