Magnesium oxide diffusion coefficient

The impurity diffusion coefficient of Fe impurities in a magnesium oxide, MgO, single crystal is given in Table 7.7(e). Estimate the activation energy for diffusion. 

John H. Hensler University of Melbourne) I was particularly heartened by the ratios of lattice and boundary coefficients. A similar ratio is observed in metal systems. The ratios for boundary diffusion in magnesium oxide are also of interest. If the boundary coefficient were about 10 times the lattice coefficient, this would facilitate the interpretation of the same sort of results that we have obtained. In the X-ray detection work, was there any evidence of a preferred orientation relationship between the two phases ... 

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