Formation and analysis of SiC coating layer on carbon short fiber

SiC-coated carbon fibers for aluminum-carbon composites were synthesized with carbothermal reduction. For the SiC layer formation on the surface of carbon fiber, silica sol was coated and heat treated at a temperature of 1460 and 1500 degrees C. SiC layer formation by carbothermal reduction complete at above 1500 degrees C for 1 h. From TGA in atmosphere, SiC coating effectively protected against the oxidation of graphite. The thickness of the SiC coating layer ranged from 150 to 300 nm and the layer was formed homogenously along the surface of carbon fiber. As the first step of reaction for SiC formation, it is generally accepted that SiO is formed and vaporized in interface between fiber and silica. It is analogized in this work that the SiO vapor reacts directly with carbon fiber, resulting in formation of SiC phase. From the TEM results, the SiC layer was confirmed as a ZnS-type FCC structure. Copyright (C) 2010 John Wiley & Sons, Ltd.