A study of silica coatings on the surface of carbon or graphite fiber and the interface in a carbon/magnesium composite

A study has been made of the method of depositing a silicon dioxide coating on the surface of carbon or graphite fibers and of the interface in C/Mg composites manufactured by vacuum pressure infiltration: the mechanical properties of the materials were also studied. For the coating process, the fibers were passed through a toluene solution containing a silicon-based organometallic compound and chloride, following which hydrolysis and pyrolysis of the organometallic compound occurred to form a thin and uniform silicon dioxide coating on the surface of the fibers. The air-stable silicon dioxide coating facilitates wetting and bonding between carbon or graphite fibers and liquid magnesium. The carbon- and graphite-fiber-reinforced magnesium composites were fabricated by vacuum/pressure infiltration processing. Special attention was focused on analysis of the structure of the coating which was deposited by the solution immersion process with the aid of analytic instruments such as SEM, EDAX, TEM, XPS and SAM. Manufacturing processes of C/Mg composites, the interface chemical reaction, and the mechanical properties were also studied.