Synthesis and characterization of boron silicon oxycarbide glass fibers

Boron silicon oxycarbide fiber mats have been obtained through pyrolysis in inert atmosphere of sol–gel derived hybrid materials. The characterization of the preceramic hybrid fibers and the pyrolysis process reveals different boron incorporation depending on the composition. The ceramic conversion involves a series of reactions governed by the presence of the mixed bonds that implies larger phase segregation and higher graphite nanodomain size with the decrease of the number of borosiloxane bridges in the preceramic material. The formation of a mixed structure, where both Si and B are taking part on the ceramic network occurs with the excess of B that precipitates as boric acid in the surface of the fibers. These precipitates can cause pores in the surface of the pyrolyzed fiber.