Synthesis of C/SiC core-shell fibers through siliconization of carbon fibers with SiO gas in semi-closed reactor

Abstract

Novel C/SiC core-shell fibers have been synthesized through incomplete conversion of carbon fibers by their siliconization with SiO gas. The synthesis was performed in the laboratory-made semi-closed batch-type reactor at 1380 °C for 3 h using a 9:1 M ratio mixture of Si and SiO2 powders as a solid source of SiO gas. The conversion rate of carbon into SiC was 34.0%. All synthesized fibers had a distinct C/SiC core-shell composite structure. The fiber product was of fairly good uniformity in respect of the shell thickness which varied approximately from 0.6 μm to 0.8 μm depending on the location of fibers inside the reactor. It was revealed that the formation of the shell was the result of inward growth of the SiC product layer. The effectiveness of the proposed semi-closed reactor for the synthesis of C/SiC core-shell fibers has been demonstrated.