The Prediction of the Bulk Modulus and its Temperature-Derivative of the Crystalline β-SiC Ceramic

Abstract

Abstract The prediction of the isothermal bulk modulus BT and the temperature-derivative (∂BT/∂T)p of crystalline silicon carbide (β -SiC) from experimental data are presented in this work. Using the experimental measurements of the coefficient of thermal expansion found by Z. Li and R. C. Bradt and the empirical value of the Anderson parameter, the variations in bulk modulus as a function of temperature and pressure are traced. Both BT and its temperature-derivative were calculated within the temperature range of 273-1573K. The bulk modulus has been found to decrease by 2.4% from its value at 273K upon heating to a temperature of 1573K. The temperature derivative of the bulk modulus decreases from − 0.003 GPa/K at 273K to a minimum of -0.0046 at Debye's temperature (1173K), and then increases again as the temperature increases. The bulk modulus has been also calculated by thermodynamical equations for the purpose of comparison, where the empirical and the thermodynamical results match to within a negligible margin of error. Both results for BT were compared to previous LDA predictions and were found to deviate by 1.72% at 237K to 5.27% at 937K, respectively. The bulk modulus BT has also been investigated as the pressure is varied from 0 to 70 GPa, where BT has been found to increase from 226.9 GPa at 0 GPa to 513.9 GPa at 70 GPa.