Mechanical properties and oxidation resistance of phenolic formaldehyde interlocking CNTs-Cf/SiC composite

Abstract To improve the mechanical properties and oxidation resistance of short carbon fiber reinforced silicon carbide matrix composites, carbon nanotubes (CNTs) were grown in-situ on carbon fiber surfaces through continuous CVD, a small amount of phenolic formaldehyde (PF) was added to the matrix to densify the composite and interlock the fiber and the matrix. The CNTs-C f /PF/SiC composite was fabricated by combining pre-casting and hot-pressing. Microstructural analyses revealed that CNTs were successfully grown on carbon fiber surfaces with entangled structures, while PF presented cobweb-like structure which tightly bonded the fiber and the matrix. Compared with CNTs-C f /SiC and C f /SiC, the flexural strength of CNTs-C f /PF/SiC increased by 15.27% and 51.95%. After heat treatment, the weight loss of CNTs-C f /PF/SiC reached 21.05%, and 31.9% of flexural strength retained after 15 thermal shock cycles at 1400 °C. These enhanced properties were indicative of its enormous potential to replace traditional C f /SiC composite.