In the present investigation, composite materials consisting of the particles of SiC or Si₃N₄ and aluminum-silicon alloy were prepared. The thermal diffusivity (a) and the specific heat (c_p) were measured in the range from room temperature to about 400°C and the thermal conductivity (λ) was calculated from the relation of λ=a·c_p·ρ.
The results obtained are summarized as follows:
(1) The thermal diffusivity of each specimen gradually decreased with increasing temperature and its temperature dependence was similar to that of the aluminum alloy. The thermal diffusivity also decreased with an increase in the content of SiC or Si₃N₄.
(2) The specific heat of each specimen increased with increasing temperature and slightly decreased with an increase in SiC or Si₃N₄ content below 200°C.
(3) The thermal conductivity did not increase with increasing temperature below about 250°C, above which they started to increase gradually with increasing temperature.