Interdiffusion in the System MgO-MgAl2O4 |
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Authors: | W P WHITNEY II V S STUBICAN |
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Affiliation: | Department of Material Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802 |
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Abstract: | Interdiffusion coefficients in single-crystal MgO were determined using an MgO-MgAl2O4 diffusion couple. For a concentration of 1 mol% Al2O3 in MgO, the interdiffusion coefficient can be expressed as D =2.0±0.2 exp (?76,000±3,000/ RT ) for the MgO-MgAl2O4 couple. This relation compares well with previous measurements in the MgO-Al2O3 system. The interdiffusion coefficients, which increased with the mol fraction of cation vacancies, were in the range of 10?8 to 10?10 cm2s?1 for the concentrations and temperatures studied. Diffusion was enhanced below 1640°C if powdered MgAl2O4 was used. Self-diffusion coefficients for Al3+ ions in MgO were calculated; Al3+ diffuses faster than Cr3+ in MgO. |
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