Skołyszewska-Kühberger Barbara, Reichmann Thomas L, Ganesan Rajesh, Ipser Herbert
Department of Inorganic Chemistry/Materials Chemistry, University of Vienna, A-1090 Wien, Austria.
Indira Gandhi Center for Atomic Research, Kalpakkam, Tamilnadu, India.
CALPHAD. 2014 Mar;44:14-20. doi: 10.1016/j.calphad.2013.07.005.
Cadmium vapor pressures were determined over Ce-Cd samples by an isopiestic method. The measurements were carried out in the temperature range from 690 to 1080 K and over a composition range of 48-85 at% Cd. From the vapor pressures thermodynamic activities of Cd were derived for all samples at their respective sample temperatures, and partial molar enthalpies of Cd were obtained from the temperature dependence of the activities. With these partial molar enthalpies the Cd activities were converted to a common temperature of 823 K. By means of a Gibbs-Duhem integration Ce activities were calculated, using a corresponding literature value for the two-phase field (CeCd+L) as integration constant. Finally integral Gibbs energies were calculated for the composition range 48-100 at% Cd with a minimum value of -37 kJ g-atom at 823 K in the phase CeCd. Phase boundaries of the intermetallic compounds CeCd, CeCd, CeCd, and CeCd were estimated from the vapor pressure measurements and from SEM analyses.
通过等压法测定了Ce-Cd样品上的镉蒸气压。测量在690至1080 K的温度范围内以及48 - 85原子百分比的镉组成范围内进行。从蒸气压得出了所有样品在各自样品温度下镉的热力学活度，并从活度的温度依赖性获得了镉的偏摩尔焓。利用这些偏摩尔焓，将镉的活度转换到823 K的共同温度。通过吉布斯-杜亥姆积分计算铈的活度，使用两相区（CeCd + L）的相应文献值作为积分常数。最后，计算了镉含量在48 - 100原子百分比范围内的积分吉布斯自由能，在823 K时，CeCd相中的最小值为-37 kJ·克原子。根据蒸气压测量和扫描电子显微镜分析估计了金属间化合物CeCd、CeCd、CeCd和CeCd的相界。
