Effect of high pressure on the formation of ordered phases in Ta-C systems
This paper considers the effect of pressure on the completion of the transformations TaC /SUB x/ Ta/sub 4/C/sub 3/ and TaC /SUB x/ Ta/sub 2/C. The data show that in the samples with C/Ta = 0.68 and 0.71, the applied pressure substantially increases the diffraction peak heights of the ordered phases, Ta/sub 4/C/sub 3/ and Ta/sub 2/C. In samples with C/Ta = 0.76, high pressure does not generally increase the intensities of the diffracted peaks of Ta/sub 4/C/sub 3/ and Ta/sub 2/C, however the equilibrium between them is displaced to the side of increased Ta/sub 2/C content. In one of the samples a complete disappearance of the disordered TaC /SUB x/ is not observed. It is concluded that high pressure ( about7GPa) promotes the transition of nonstoichiometric TaC /SUB x/ into ordered Ta/sub 4/C/sub 3/ and Ta/sub 2/C as well as broadens the existence region of the latter. A complete transformation of TaC /SUB x/ into the ordered phase does not occur even at pressures up to about 9 GPa.
- Research Organization:
- Inst. of Problems in Materials Science, Academy of Sciences of the Ukranian SSR, Chernov State Univ.,
- OSTI ID:
- 6461019
- Journal Information:
- Inorg. Mater. (Engl. Transl.); (United States), Journal Name: Inorg. Mater. (Engl. Transl.); (United States) Vol. 20:10; ISSN INOMA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CARBIDES
CARBON COMPOUNDS
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
EQUILIBRIUM
PHASE STUDIES
PHASE TRANSFORMATIONS
PRESSURE EFFECTS
REFRACTORY METAL COMPOUNDS
TANTALUM CARBIDES
TANTALUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS