Fabrication and tensile behaviors of mini-C/SiC composites reinforced by Si3N4 nanowires

The carbon fiber tows covered by Si3N4 nanowires were densified using chemical vapor infiltration (CVI) technique to form mini-C/SiC composites reinforced by Si3N4 nanowires (Mini-C/SiC-Si3N4-NW). The tensile behaviors of the composites were examined, and the associated damage evolutions were monitored by the acoustic emission (AE) method. Compared with the traditional mini-C/SiC composites (Mini-C/SiC), the matrix strength and fracture strength of Mini-C/SiC-Si3N4-NW were increased by about 100% and 8%, respectively, due to the introducing of Si3N4 nanowires reinforcements. The density of Si3N4 nanowires and volume fraction of carbon fibers played important roles in the matrix strength and fracture strength of the mini-composites, respectively. Moreover, owning to the extra deposition surfaces provided by the Si3N4 nanowires, the CVI cycles of Mini-C/SiC-Si3N4-NW were 50% shorter than that of the Mini-C/SiC.