The System HfO2-Y2O3-Er2O3 |
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Authors: | Elena R Andrievskaya Lidia M Lopato Vasily P Smirnov |
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Affiliation: | Institute of Materials Science Problems, 252142, Kiev, Ukraine |
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Abstract: | A mathematical model of the liquidus surface based on a reduced polynomial method was proposed for the system HfO2-Y2O3-Er2O3. The results of calculations according to this model agree fairly well with the experimental data. Phase equilibria in the system HfO2-Y2O3-Er2O3 were studied on melted (as-cast) and annealed samples using X-ray diffraction (at room and high temperatures) and micro-structural and petrographic analyses. The crystallization paths in the system HfO2-Y2O3-Er2O3 were established. The system HfO2-Y2O3-Er2O3 is characterized by the formation of extended solid solutions based on the fluorite-type (F) form of HfO2 and cubic (C) and hexagonal (H) forms of Y2O3 and Er2O3. The boundary curves of these solid solutions have the minima at 2370°C (15. 5 mol% HfO2, 49. 5 mol% Y2O3) and 2360°C (10. 5 mol% HfO2, 45. 5 mol% Y2O3). No compounds were found to exist in the system investigated. |
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