Thermal properties of silicon carbide composites fabricated with chopped Tyranno (R) Si-Al-C fibres

Thermal diffusivity, a, and thermal conductivity, K, between room temperature and 600 K were investigated for SiC composites containing 0-50 mass% of Tyranno((R)) Si-Al-C (SA) fibre (mean length: 394 mu m) hot-pressed at 1800 degrees C for 30 min under a pressure of 31 MPa. The monolithic SiC specimen possessed kappa 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 K 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 K was marginal. (c) 2005 Elsevier Ltd. All rights reserved.