SELF-DIFFUSION OF BERYLLIUM IN UNIRRADIATED, COLD-PRESSED AND SINTERED BERYLLIUM OXIDE

Technical Report · Wed Jan 29 04:00:00 EST 1964

DOI:https://doi.org/10.2172/4126859· OSTI ID:4126859

de Bruin, H. J.; Watson, G. M.

Diffusion of beryllium-7 through polycrystalline unirradiated specimens of BeO was studied as a preliminary step to a study of diffusion in irradiated material. Beryllium-7 was deposited on one end of cylindrical specimens by exchange and adsorption from aqueous solution. The depth of penetration perpendicular to the surfaces of deposition was determined after annealing the specimens at pre-determined conditions. A simple lapping device of high precision was developed to determine penetration depths. For the polycrystalline cold-pressed and sintered BeO studied, the diffusion behavior between 1150 and 1800 deg C is described by the empirical relation: D = 2.49 x 10/sup -3/ exp -- (62.5 x 10/sup 3//RT) cm/sup 2//sec. A diffusion model is proposed based on vacancy migration which suggests identical activation energies for diffusion in both a and c directions in single crystals and predicts an activation energy of the correct order oi magnitude. Furthermore, the model p dicts that the frequency factor in the direction pexpendicular to the c axis should be about 50% higher than that parallel to the c axis. (auth)

• Research Organization: Oak Ridge National Lab., Tenn.
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-18-008798
• OSTI ID: 4126859
• Report Number(s): ORNL-3526
• Country of Publication: United States
• Language: English

Related Subjects

ADSORPTION
ANNEALING
BERYLLIUM
BERYLLIUM 7
BERYLLIUM OXIDES
COLD WORKING
COMPACTING
CRYSTALS
CYLINDERS
DEFECTS
DIFFUSION
DISTRIBUTION
EXCITATION
HIGH TEMPERATURE
IRRADIATION
LABORATORY EQUIPMENT
LATTICES
METALS, CERAMICS, AND OTHER MATERIALS
QUANTITATIVE ANALYSIS
SINTERED MATERIALS
SOLUTIONS
SURFACES
VACANCIES
WATER