Thermodynamic properties of Co6W6C compound

Abstract:

Co₆W₆C is a ternary compound that is often found in the preparation process of WC-Co cemented carbides. Its content and phase transition have significant effect on the performance of cemented carbides. However, there are limited investigations on the thermodynamic parameters, thermal stability and phase transition characteristics of this compound in the literature. In the present work, W, Co and carbon black powders were used as raw materials to prepare the single phase Co₆W₆C compound. By optimizing the preparation parameters, i.e. with the carbon black addition of 1.06wt.% and the reaction temperature kept at 1000°C for 1h in the vacuum condition, pure compound of Co₆W₆C was made. Subsequently, by a series of experimental measurements, the thermodynamic parameters of Co₆W₆C were obtained, based on which thermodynamic calculations were performed. The thermodynamic properties such as the standard molar entropy ( ),standard molar enthalpy of formation ( ), isobaric heat capacity (C_p), enthalpy ( ), entropy ( ) and Gibbs free energy (G) were obtained as a function of temperature.

Key words:Co₆W₆C, vacuum;reaction, thermodynamic;calculation