Preparation and oxidation property of ZrB2-MoSi2/SiC coating on carbon/carbon composites

In-situ synthesis of SiC nanofibers for improving the oxidation resistance of graphite

“…(6), and the reaction between SiO and CO could result in the production of SiC. In these conditions, SiC could be produced in the form of nanofibers, as indicated by other investigations [13,20].…”

“…13 demonstrates that the SiC nanofibers bridged the coating microcracks and defects, thus inhibiting the promotion of defects subjected to thermal stresses and also, preventing the oxygen diffusion through the pores. Consequently, the good oxidation resistance of the protected secondary coating could be attributed to the SiC nanofibers [13,14]. It is suggested that the formation mechanism of nanofibers be investigated in the future studies.…”

“…1, the B 2 O 3 was not observed in the coating surface phase analysis. It might have been penetrated to the coating pores by the gravity-induced flow and transferred below the powders pack, or it might have been vaporized because of the high vapor pressure [13,21]. Moreover, B 2 O 3 and SiO 2 could react forming an amorphous borosilicate glass preventing the diffusion of oxygen.…”

“…(12), is often in the form of nanofibers [13,20]. So the growth of the SiC nanofibers was attributed to the gaseous reaction of SiO with CO.…”

“…Zhang [13] indicated that the ZrB 2 -MoSi 2 /SiC coated carbon/carbon composites showed good anti-oxidation ability at 1273 K and self-sealing performance and oxidation resistance at 1773 K due to the SiC nano-whiskers covering the original cracks and the formation of ZrSiO 4 and SiO 2 glaze. Moreover, Chu [14] also applied a multilayer SiC and SiC nanowire coating on a carbon-carbon composite by the hybrid chemical vapor deposition (CVD).…”