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

The prediction of the isothermal bulk modulus B T and the temperature-derivative ∂ B T / ∂ T P of crystalline silicon carbide β - S i C 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 B T and its temperature-derivative were calculated within the temperature range of 273-1573 K. The bulk modulus has been found to decrease by 2.4% from its value at 273 K upon heating to a temperature of 1573 K. The temperature derivative of the bulk modulus decreases from -0.003 GPa/K at 273 K to a minimum of -0.0046 at Debye's temperature (1173 K), 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 B T were compared to previous LDA predictions and were found to deviate by 1.72% at 237 K to 5.27% at 937 K, respectively. The bulk modulus B T has also been investigated as the pressure is varied from 0 to 70 G P a , where B T has been found to increase from 226.9 G P a at 0 G P a to 513.9 G P a at 70 G P a . Graphical Abstract