Date of Award
Doctor of Philosophy (PhD)
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:
Type II Cells:
Type III Cells:
Type IV Cells:
Type I and II cells were used to yield the standard free energy changes corresponding to the reaction
at two different sulfur partial pressures. Type III cells were used to determine the standard free energy changes for the reaction.
Type IV cells were used to determine the standard free energy changes for the reaction
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.
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.