![]() ![]() Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. Thus simple equations could be derived for heats of formation, mixing and phase transition in this system which can be used in the future in CALPHAD type calculations of phase equi-libria that obtain the extent of fluorite solid solution at different temperatures. Comparison of measured values with those predicted from the binary systems using the Kohler equation suggests that the ternary excess term is zero within experimental error. Enthalpies of mixing in the ternary CeO2-CaO-ZrO2 system were calculated from enthalpies of drop solution measured by high temperature oxide melt solution calorimetry for a set of newly synthesized ternary fluorite samples. ![]() Enthalpies of transformation of monoclinic zirconia to the cubic fluorite phase (stable at high temperature) and of rocksalt calcia to the hypothetical fluorite phase were constrained by experimental data. The interaction parameters for binary systems are U CeO2-ZrO2 = 49.9 ± 2.4 kJ mol -1, U CaO-ZrO2 = -78.0 ± 16.7 kJ mol -1 and U CaO-CeO2 = 53.1 ± 21.5 kJ mol -1. Using experimental thermodynamic data from binary systems ZrO2-CeO2, CaO-CeO2 and CaO-ZrO2, the present work fitted the enthalpies of mixing to regular solid solution models. The fluorite phase in CeO2-CaO-ZrO2 is important in nuclear energy and fuel cell applications yet one lacks quantitative evaluation of its composition range and thermodynamic properties.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |