Reactivity and thermal behaviour of Cu-Si/SiC composites: effects of SiC oxidation

The thermal conductivity and thermal expansion of Cu-Si/SiC particle reinforced composites, fabricated by pressure infiltration, have been investigated. To reduce (or avoid) reaction of liquid Cu with the SiC reinforcement, which has deleterious effects on both thermal conductivity and thermal expansion coefficient, the SiC particles were oxidised at 1000 degrees C before infiltration. While a small reduction in extent of reaction could be observed, manifest in a slight increase of thermal conductivity, the absolute value of the thermal conductivity was very low (between 40 and 70 W m(-1) K-1), which is even lower than that of a Cu/SiO2 reference sample with a similar volume fraction of ceramic phase (160 W m(-1) K-1). The pre-oxidation treatment increased the coefficient of thermal expansion from 9 to 11 ppm K-1.