Thermodynamics and kinetics of sintering of Y2O3 |
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Authors: | Kimiko Nakajima Ricardo H R Castro |
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Affiliation: | Department of Materials Science and Engineering, University of California, Davis, CA, USA |
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Abstract: | Surface energy (γS) and grain boundary energy (γGB) of yttrium oxide (Y2O3) were determined by analyzing the heat of sintering (ΔHsintering) using differential scanning calorimetry (DSC). The data allowed quantification of sintering driving forces, which when combined with a thorough kinetic analysis of the process, provide better understanding of Y2O3 densification as well as insights into effective strategies to improve its sinterability. The quantitative thermodynamic study revealed moderate thermodynamic driving force for densification in Y2O3 (as compared to other oxides) represented by a dihedral angle of 152.7° calculated from its surface and grain boundary energies. The activation energy was determined as 307 ± 61 kJ/mol, consistent with activation energies previously reported for processes relevant to sintering of Y2O3, such as Y3+ diffusion and grain boundary mobility. Finally, we propose that a refined deconvolution study on the DSC curve for Y2O3 sintering, combined with the associated material's microstructure evolution, may help identify shifts in sintering mechanisms, and therefore, specific activation energies at increasing temperatures. |
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Keywords: | densification sinter/sintering thermodynamics yttrium/yttrium compounds |
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