A COMPARATIVE STUDY OF TWO GRADES OF BeO

Technical Report · Wed Nov 01 04:00:00 EST 1961

OSTI ID:4807865

Reeve, K D; Ramm, E J

Pechiney and Brush UOX BeO differ markedly in fabrication behavior, only Brush UOX being readily sinterable. A comparative study of the two powders has shown few outstanding differences in powder propenties. Both are of high purity but contain free and combined moisture to the extent of about 1.5%. Pechiney BeO has a larger mean crystallite size (0.2 to 0.3 mu ) than Brush UOX (0.l to 0.15 mu ) and a larger range of crystallite size, and both contain a small proportion of crystallites of size 1 mu and larger. The tap density of UOX is much lower than that of Pechiney, and its surface area is higher by a factor of two. UOX BeO can be hotpressed or cold-pressed and sintered to high densities at 1400 and 1500 deg C, respectively, which are approximately 300 deg C lower than those required for Pechiney. Grain size of fabricated material increases with fabrication temperature in both grades, and at the same temperatures is larger for UOX than Pechiney. However, at comparable densities grain sizes are also comparable for the two materials. The bend strength at room temperature of hot- pressed Pechiney BeO reaches a maximum of approximately 30,000 psi when pressed at 1750 deg C. Above this temperature the strength falls because of increasing crystallite size. Cold-pressed and sintered Brush UOX appears weaker, possibly from weaker grain boundary cohesion. Cold-pressed and sintered BeO is considered worthy of most intensive study as an irradiation resistant material, and suggestions are given for improving its strength and homogeneity and decreasing its crystallite size. (auth)

• Research Organization: Australia. Atomic Energy Commission Research Establishment, Lucas Heights, New South Wales
• NSA Number: NSA-16-009183
• OSTI ID: 4807865
• Report Number(s): AAEC/E-80
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BERYLLIUM OXIDES
COLD WORKING
CRYSTALS
DENSITY
GRAIN BOUNDARIES
GRAIN SIZE
HOT WORKING
METALS, CERAMICS, AND OTHER MATERIALS
POWDERS
PRESSURE
SINTERING
TEMPERATURE
TENSILE PROPERTIES