Thermodynamic and kinetic study of a Vapor Phase Transport (VPT) reaction: The system NbSe2-iode
Abstract
Kinetic and thermodynamic studies are used to investigate chemical vapor transport of niobium diselenide by iodine processes. A kinetic study, operated in a multizone furnace, strongly depends on thermal profile (2 or 3 zones), on available NbSe2 mass, on initial iodine concentration, and on flux perturbations. Biggest crystals are obtained in the 3 zones profile with a 7.8 mg/hr transport speed. A thermodynamic study of transport was done from total pressure measurements of NbSe2 + iodine mixing. The behavior of iodine, selenium, and niobium diselenide under the same conditions shows that iodine and selenium dissociations both occur with high temperature NbI3 iodide formation. Equilibria temperature is close to 740 +/- 10C.
- Publication:
-
Material Sciences under Microgravity Conditions
- Pub Date:
- February 1987
- Bibcode:
- 1987msum.symp..559V
- Keywords:
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- Niobium Iodides;
- Reaction Kinetics;
- Selenides;
- Thermodynamics;
- Vapor Phase Epitaxy;
- Concentration (Composition);
- Convection;
- Diffusion Coefficient;
- Microgravity Applications;
- Space Commercialization;
- Thermodynamics and Statistical Physics