Date of Award
7-1982
Degree Type
Thesis
Degree Name
Doctor of Philosophy (PhD)
Department
Metallurgy
Supervisor
D.A.R. Kay
Abstract
The thermodynamics of rare earth-oxygen-sulfur systems was studied at high temperatures using the following four types of oxygen concentration cells.
Type I Cells:
[equation removed]
Type II Cells:
[equation removed]
Type III Cells:
[equation removed]
Type IV Cells:
[equation removed]
Type I and II cells were used to yield the standard free energy changes corresponding to the reaction
[equation removed]
at two different sulfur partial pressures. Type III cells were used to determine the standard free energy changes for the reaction.
[equation removed]
Type IV cells were used to determine the standard free energy changes for the reaction
[equation removed]
Combining the experimental results for the above three-reactions with the values of ΔGfº for Cu₂S and Ag₂S, the standard free energies of formation of La₂O₂SO₄, Pr₂O₂SO₄, Nd₂O₂SO₄, Sm₂O₂SO₄, Eu₂O₂SO₄, Gd₂O₂SO₄, La₂O₂S, Pr₂O₂S, Nd₂O₂S, Sm₂O₂,S, Eu₂O₂S, Gd₂O₂S, Y₂O₂S and Ce₂O₂S were determined at high temperatures. In addition, the standard free energy changes for oxidation of Tb₂O₂S and Dy₂O₂S to Tb₂O₂SO₄ and Dy₂O₂SO₄ were determined.
The above data were used to construct the phase stability diagrams for the rare earth-oxygen-sulfur systems at high temperatures.
Recommended Citation
Dwivedi, Ratnesh Kumar, "Determination of the Thermodynamic Properties of Rare Earth-Oxygen-Sulfur Systems at High Temperatures" (1982). Open Access Dissertations and Theses. Paper 3897.
http://digitalcommons.mcmaster.ca/opendissertations/3897