Effect of dispersibility of vapor-grown carbon nanofiber on the mechanical strength of silicon carbide composite

Abstract

The conditions for the fabrication of high-density silicon carbide (SiC) composite with vapor-grown carbon fiber (VGCF) addition were investigated by hot-pressing technique, using the sintering aids (8 mass% Al4C3 and 2 mass% B4C). The acid treatment was conducted in order to enhance the dispersibility of VGCF in the matrix, owing to the addition of COO- group to the surface of VGCF. Due to this treatment, the relative density and fracture toughness of SiC composite with 6 mass% VGCF addition hot-pressed at 1800 deg C for 1 h (pressure: 62 MPa) attained 99.0% and 5.7 MPa m1/2, respectively. The reduced length of pulled-out VGCF, compared to the case of SiC composite with as-prepared VGCF addition, was considered to be occurred by the enhanced friction between VGCF and SiC matrix, due to the acid treatment.