A novel method of silicon carbide coating to protect porous carbon against oxidation

Abstract To improve the chemical stability and oxidation resistance of a carbon material, silicon carbide (SiC) was coated on porous carbon by impregnation. The porous carbon was impregnated with a silicone oil/n-hexane solution as a precursor for the SiC coating layer. The impregnated porous carbon was heat-treated at 1520 °C in an atmosphere of Argon (Ar). X-ray diffraction (XRD) analysis demonstrated an amorphous porous carbon with a coated layer of β-SiC in crystalline phase. Scanning electron microscope (SEM) observations revealed a thin layer of SiC coated on the surface of the carbon spheres although the SiC layer was not sufficiently dense. The oxidation of the SiC-coated porous carbon was remarkably retarded because of its coating with SiC. In addition, the compressive strength of the SiC-coated porous carbon was almost two times higher than that of the pristine porous carbon.