金属元素Cu的热力学性质

Thermodynamic properties of pure elemental Cu

采用SGTE纯单质数据库中Gibbs能的表达式,结合JANAF热力学实验数据,用最小二乘法对金属元素Cu的Gibbs能表达式进行重新评估。重新评估后的转变热容、转变焓和转变熵分别为-0.187 J/(mol.K)、13.138 kJ/mol和9.675 J/(mol.K),与实验数据符合很好。运用Debye-Grüneisen模型研究Cu从0 K到熔点的热力学性质,结果发现模型计算的低温热容值偏低,从而导致模型计算的转变熵和Gibbs能偏大。运用Debye-Grüneisen模型研究过冷液体的热力学性质,并通过保持熔点热容、焓和熵值的连续性,得到液相Cu的热容和Gibbs能等热力学性质,结果与实验值数据符合较好。

The transition data and Gibbs energy functions of pure elemental Cu in SGTE database were reassessed using the least-square method and adopting the newly available thermochemical reference JANAF data in the fourth edition. The results of transitional heat capacity, enthalpy and entropy are -0. 187 J/（mol · K）, 13. 138 kJ/mol and 9. 675 J/（mol · K）, respectively, and these data agree well with JANAF data. Debye-Griineisen model was applied to study the thermodynamic properties of fcc and supercooled liquid phase from 0 K to 1 357.77 K. It is found that the heat capacity of Debye-Grüneisen model at low temperature is lower than experimental data and leads to the higher transitional entropy and Gibbs energy. Keeping the continuum of cp, H and S between the supercooled and real liquid phase of Cu at melting point, the thermodynamic properties of liquid Cu can be obtained and they agree well with JANAF data as well.