Co6W6C化合物的热力学研究

Thermodynamic properties of Co6W6C compound

摘要:

以高纯钨、钴、碳粉为原料,在真空条件下制备获得物相纯净的Co₆W₆C化合物,对Co₆W₆C进行系列实验测定并结合计算得出了其相关的热力学参数。结果表明：在原料粉中碳含量为1.06wt.%、真空反应温度为1000℃、保温时间为1h的条件下,可制备获得物相纯净的Co₆W₆C。结合其等压热容及1173K下氧化反应的反应焓测定结果,通过计算获得了Co₆W₆C的标准摩尔熵( )、标准摩尔生成焓( )等热力学参数以及其等压热容(C_p)、焓( )、熵( )和吉布斯自由能( )等基础热力学参量随温度变化的函数关系。

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.