Determination of the thermodynamic activities of NaBr and DyBr3 in the phases of the NaBr–DyBr3 system at 863 K by Knudsen effusion mass spectrometry

• Published in: Journal of alloys and compounds Vol. 379; no. 1-2; pp. 1 - 7
• Main Authors: Hilpert, Klaus, Miller, Miroslaw
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 06.10.2004; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Knudsen effusion mass spectrometry; Materials science; NaBr–DyBr3 system; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Phase diagrams of other materials; Physics; Thermochemistry; Vaporization; Thermochemistry; Knudsen effusion mass spectrometry; NaBr–DyBr3 system; Vaporization; Dysprosium bromides; Knudsen effusion; Phase diagrams; Thermodynamic activity; Sodium bromides; Experimental study; Heat of formation; NaBr-DyBr3 system
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2004.02.026

The vaporization of the phases of the NaBr–DyBr3 system was studied in the temperature range of 703–1025K by the use of Knudsen effusion mass spectrometry. The gaseous species NaBr, (NaBr)2, DyBr3, (DyBr3)2, NaDyBr4, and Na2DyBr5 were identified in the equilibrium vapor. Thermodynamic activities of NaBr and DyBr3 were evaluated over the complete concentration range of the system at 863K by use of heterogeneous equilibria and the ion intensity ratio integration method. The data obtained are discussed and compared with the known phase diagram of the NaBr–DyBr3 system. Gibbs energy of formation of 3NaBr × DyBr3(s) at 703K, −13.1±2.0kJmol−1, resulted from thermodynamic activities of components.