Sintering Kinetics of Beryllia |
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Authors: | T E CLARE |
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Affiliation: | Australian Atomic Energy Commission, Research Establishment, Lucas Heights, New South Wales, Australia |
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Abstract: | Compacts of sulfate-derived beryllia were sintered, for various times, in nitrogen at 1050° to 1500°C. The applicable equation for densification is This is predicted by the Coble intermediate-stage volume diffusion sintering model for material showing the observed (time)½ dependence of grain size on time. Apparent diffusion coefficients for sintering are near those for oxygen diffusion in BeO but it is not possible to make a firm conclusion on the rate-controlling ionic species. The activation energy for diffusion differs from that for grain growth; therefore the relation between porosity and grain size is not independent of temperature. Mathematical analysis shows that under certain conditions there may be an optimum temperature at which a required density can be attained with a minimum grain size. |
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