DIFFUSION OF BERYLLIUM IN BERYLLIUM OXIDE. PART II

Publisher Website
Google Scholar
Abstract
The diffusion coefficient for Be in BeO was measured as a function of temperature for a group of identical polycrystalline BeO samples, as well as in a variety of types of BeO samples. The temperature dependence follows two straight lines on a log D--l/T graph, the lines lntersecting at 1725 deg C. The lines correspond to the equatlons: D = 1.37 exp(--91.9 kcal/mole)/RT (1550 to 1725 deg C), and D = 1.10 x 10/sup -//sup 4/ exp(--36.15 kcal/mole)/RT (1725 to 2000 deg C). The diffusion coefficient at 1800 deg C for this particular set of samples is approx. 40 times less than that for a different type of BeO, as previously published. The significance of certain material parameters is consldered; no correlation is noted between the magnitude of the diffusion coefficient and any single parameter. The observed wlde varlations in D (a maximum of 40x at 1800 deg C) are probably the net result of simultaneous changes in many of the significance of cereters of the polycrystalline ssmples. Lattice diuffusion the inferred principal mode of diffusion in all cases. (auth)

This publication has 0 references indexed in Scilit: