CHEMICAL STABILITY OF BERYLLIUM BORIDES AGAINST ATTACK BY OXYGEN, NITROGEN AND CARBON AT HIGH TEMPERATURES

Journal Article · Sun May 01 04:00:00 EDT 1960 · Zhur. Priklad. Khim.

OSTI ID:4167854

Markevich, G S; Markovskii, L Ya

The various Be borides, prepared by direct calcination of elementary powders, were found to have widely different resistances when heated to high temperatures in air and in contact with carbon. A typical parabolic weight loss versus time curve was obtained, corresponding to removal of B/sub 2/O/sub 3/ formed by oxidation and indicating the formation of a protective layer and the existence of a diffusion controlled reaction. The compounds containing the largest amounts of B, such as BeB/sub 2/, BeB/sub 4/, and BeB/sub 6/ were found to be the most stable, when compared to the Be-rich compounds Be/sub 5/B and Be/ sub 2/B. Although the exact structure of the B-rich phases was not established, it may be assumed that they possess the complex spatial structure of boron, like the other hexaborides of the type MeB/sub 6/, thus explaining the high temperature resistance. However, even the most stable Be borides are inferior to the borides of the transition metals which remain unaffected even when heated to 2000 tained C in the presence of C, while the Be borides carburize under those conditions in the temperature range 900 to 1300 tained , forming Be/sub 2/C and exhibiting a stronger affinity of the Be toward C than toward B. (TTT)

• Research Organization: State Inst. of Applied Chemistry, USSR
• NSA Number: NSA-14-018965
• OSTI ID: 4167854
• Journal Information: Zhur. Priklad. Khim., Journal Name: Zhur. Priklad. Khim. Vol. Vol: 33
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

AIR
BERYLLIUM COMPOUNDS
BERYLLIUM OXIDES
BORIDES
CARBON
CHEMICAL REACTIONS
CHEMISTRY
COMBUSTION
CONFIGURATION
DIAGRAMS
DIFFUSION
HIGH TEMPERATURE
LAYERS
LOSSES
NITROGEN
OXIDATION
OXYGEN
POWDERS
PRODUCTION
RESIDUES
STABILITY
WEIGHT