Thermal properties of silicon carbide composites fabricated with chopped Tyranno ® Si [sbnd]Al [sbnd]C fibres

Abstract

Thermal diffusivity, a, and thermal conductivity, κ, between room temperature and 600 K were investigated for SiC composites containing 0–50 mass% of Tyranno ® Si Al C (SA) fibre (mean length: 394 μm) hot-pressed at 1800 °C for 30 min under a pressure of 31 MPa. The monolithic SiC specimen possessed κ of 32.1 W m −1 K −1 at room temperature; no significant changes were found for the SiC composite containing ≤20 mass% of SA fibre addition. However, further increases in the amount of SA fibre to 50 mass% improved κ to a maximum of 56.3 W m −1 K −1. The value of a for the SiC composite containing 40 mass% of SA fibre was 0.185 cm 2 s −1 at room temperature and decreased to 0.120 cm 2 s −1 at 600 K. In addition, SiC composites using 40 mass% of SA fibre with a carbon interface of approximately 100 nm were fabricated. The effect of this interface on a and κ was marginal.