Kinetic aspects of reaction between tantalum and carbon material (active carbon or graphite) under solar radiation heating

Fernandes, Jorge Cruz; Oliveira, Fernando A. Costa; Granier, B.; Badie, J. M.; Rosa, Luı́s Guerra; Shohoji, Nobumitsu

doi:10.1016/j.solener.2006.01.001

Cited by 26 publications

(23 citation statements)

References 9 publications

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“…[1][2][3][4][5][6][7][8][9][10] This line of work was continued after 2005 using a solar furnace at PROMES-CNRS (Laboratoire Procédés, Matériaux et Energie Solaire) in Odeillo. [11][12][13][14][15][16][17][18] During the course of these works, we managed to demonstrate that the solar furnaces are capable of concentrating the solar energy by a factor 10 4 or higher to a spot size of diameter, 5 cm (PSA) or 1 cm (PROMES-CNRS), and therefore can be used as the ecological renewable heat source to trigger high temperature reactions leading to refractory carbide synthesis.…”

Section: Introductionmentioning

confidence: 99%

Reactions of Ti, V, Nb and Ta with N2 Gas at 2000°C under Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

Shohoji

Oliveira

Rosa³

et al. 2011

Mater. Trans.

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Reactions of d-group transition metals including Ti, V, Nb and Ta with N 2 gas were investigated at target temperature of 2000 C under heating with concentrated solar beam at PROMES-CNRS in Odeillo (France). In the typical experimental setup using graphite crucible as the sample holder, synthesis of pure nitride with fcc (face centred cubic) structure was proved to be difficult on account of inevitable C 2 radical plume with high carbon activity a(C) from the graphite components and the majority of reaction products were carbo-nitride. By insertion of Sky blue filter in the solar beam path before entering into the parabolic concentrator, C 2 radical formation appeared to be efficiently suppressed and phases with high N content were synthesized. However, under conditions in which C 2 radical plume yield was considerable, nitrogen content in the reaction products became suppressed and tetragonal Nb 4 N 3 yielded in place of fcc NbN from Nb or N-deficit sub-nitride Ta 2 N in place of mono-nitride TaN formed.

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Section: Introductionmentioning

confidence: 99%

Reactions of Ti, V, Nb and Ta with N2 Gas at 2000°C under Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

Shohoji

Oliveira

Rosa³

et al. 2011

Mater. Trans.

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“…14) For the binary V-C system, the mono-carbide phase VC is incomparably more stable thermodynamically than the sub-carbide phase V 2 C and correspondingly the once formed V 2 C was fully converted to VC by prolonged heating 14) in contrast to the situations with M ¼ Mo and W in which M 2 C insisted to remain in the reaction product even after prolonged heating to 90 min. [6][7][8] …”

Section: Resultsmentioning

confidence: 99%

Carbide Phases Synthesised from C/Mo Powder Compacts at Specified Sub-Stoichiometric Ratios by Solar Radiation Heating to Temperatures between 1600°C and 2500°C

et al. 2009

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There are a number of distinguishable carbide phases in the binary Mo-C system depending on C/Mo ratio as well as on temperature. In a preceding work published in this journal, carbide formation performance for graphite/molybdenum powder mixtures at specified levels of substoichiometric C/Mo atom ratio (C/Mo = 1/1, 3/4, 2/3 and 1/2) by exposure to concentrated solar radiation in a solar furnace at PROMES-CNRS in Odeillo (France) was reported at a target temperature 1900 C. In the present work, the similar carbide synthesis experiments were carried out at 1600 C as well as at temperature exceeding 2500 C. The target temperature setting was adjusted by controlling the downward deviation of the test piece top surface position from the exact focal spot of the parabolic mirror concentrator located above. In this solar furnace at PROMES-CNRS, temperature of the test piece was raised from ambient temperature to the target temperature within fractions of a second. Reaction products detected were hexagonal -MoC 1Àx and -Mo 2 C (high temperature sub-carbide phase) depending on the C/Mo ratio in the starting material as well as on the processing temperature. No evidence of formation of cubic -MoC 1Àx was detected by X-ray diffraction analysis for any test piece examined.

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“…24,20,21) The mode of morphological development for Nb in the Group IV experiment [ Fig. 4(d)] also looks very different from that for Ti [ Fig.…”

Section: Nbmentioning

confidence: 99%

“…Similar intermediate subcarbide formation was observed for another Va-group element, Ta, during synthesis of carbide under heating with concentrated solar beam. 20) The formed sub-carbide V 2 C in meta-stable state was eventually converted to stable monocarbide VC after prolonged holding at the high temperature. 20) Under the present reaction condition of the Group III experiment with suppressed a(C)…”

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Crystal Grain Morphology Evolution over Ti, V, Nb and Ta Surface Heated in N2 Gas Environment to 2000°C by Filtered Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

Oliveira

Rosa²,

Péraudeau

et al. 2012

Mater. Trans.

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In recent attempts of reacting d-group transition metals with N 2 gas under irradiation of concentrated solar beam at temperatures around 2000°C using a standard setup with graphite specimen holder, reaction products obtained were carbo-nitrides rather than targeted nitrides on account of yield of C 2 radical plume from the graphite crucible. To suppress the interference of C 2 radical possessing high carbon chemical activity a(C) in nitriding d-group transition elements in solar furnace, we investigated effectiveness of inserting colour filters in the solar beam path. Two readily available colour filters, Sky blue and Medium yellow filters, were tested for this purpose. As reported in our earlier publications, XRD (X-ray diffraction) phase identification results indicated that insertion of the Sky blue filter was effective for suppressing C 2 radical yield under solar beam radiation to synthesize carbo-nitride with comparatively high N content. On the other hand, insertion of the Medium yellow filter did not result in so remarkable effect for suppressing carburization as the one detected with the Sky blue filter. In the present work, aspects of microstructures developed for Ti, V, Nb and Ta surfaces heated to 2000°C under exposure to colour-filtered solar beam in N 2 gas environment are reviewed. The present experimental evidences indicated that, by insertion of the Sky blue filter, appreciable crystallite grain size refinement was realized for the synthesized M(C,N) with high N content while, by insertion of the Medium yellow filter, certain extent of influence on the morphological development, that varied depending on the substrate material, was unmistakably discernible.

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Kinetic aspects of reaction between tantalum and carbon material (active carbon or graphite) under solar radiation heating

Cited by 26 publications

References 9 publications

Reactions of Ti, V, Nb and Ta with N<SUB>2</SUB> Gas at 2000°C under Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

Reactions of Ti, V, Nb and Ta with N<SUB>2</SUB> Gas at 2000°C under Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

Carbide Phases Synthesised from C/Mo Powder Compacts at Specified Sub-Stoichiometric Ratios by Solar Radiation Heating to Temperatures between 1600°C and 2500°C

Crystal Grain Morphology Evolution over Ti, V, Nb and Ta Surface Heated in N<sub>2</sub> Gas Environment to 2000°C by Filtered Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

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Kinetic aspects of reaction between tantalum and carbon material (active carbon or graphite) under solar radiation heating

Cited by 26 publications

References 9 publications

Reactions of Ti, V, Nb and Ta with N<SUB>2</SUB> Gas at 2000&deg;C under Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

Reactions of Ti, V, Nb and Ta with N<SUB>2</SUB> Gas at 2000&deg;C under Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

Carbide Phases Synthesised from C/Mo Powder Compacts at Specified Sub-Stoichiometric Ratios by Solar Radiation Heating to Temperatures between 1600&deg;C and 2500&deg;C

Crystal Grain Morphology Evolution over Ti, V, Nb and Ta Surface Heated in N<sub>2</sub> Gas Environment to 2000&deg;C by Filtered Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

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Reactions of Ti, V, Nb and Ta with N<SUB>2</SUB> Gas at 2000°C under Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

Reactions of Ti, V, Nb and Ta with N<SUB>2</SUB> Gas at 2000°C under Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS

Carbide Phases Synthesised from C/Mo Powder Compacts at Specified Sub-Stoichiometric Ratios by Solar Radiation Heating to Temperatures between 1600°C and 2500°C

Crystal Grain Morphology Evolution over Ti, V, Nb and Ta Surface Heated in N<sub>2</sub> Gas Environment to 2000°C by Filtered Concentrated Solar Beam in a Solar Furnace at PROMES-CNRS