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.