Abstract
This paper reports the thermal properties of HIP-sintered composite of diamond/SiC and its practical use to high pressure anvils. First, thermal diffusivities, specific heat capacities and expansion coefficients of the composites were measured. The obtained values were smaller than those of pure diamond and larger than SiC, respectively. The thermal conductivity is high and the expansion coefficient is low in the products whose starting materials consisted of diamond with large grain size. The photomicrographs of these products indicate that larger amount of diamond exists and the average grain sizes of diamond are large.
Secondly, temperatures of composites were measured when they were used as the anvils in 6-8 type high-pressure apparatus. Two sets of thermocouples were attached on the anvils and the temperatures under pressures were measured. Temperatures at an arbitrary point between two thermocouples were calculated using the conductivity measured in the first experiment. On the calculation, the shapes of anvils were assumed to be spherical shells instead of cubes. Since the calculated temperatures are fairy close to the measured values, this model seems to be one of methods to predict the temperatures of anvils.
