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Synthesising carbo-nitrides of some d-group transition metals using a solar fur...
Shohoji, Nobumitsu; Oliveira, F. A. Costa; Rosa, Luís Guerra; Fernandes, Jorge Cruz; Magalhães, Teresa; Coelho, Manuel Caldeira; Rodriguez, JoséCarbo-nitride synthesis was undertaken using a solar furnace at PSA in flowing N2/Ar gas mixture under total pressure 1 atm and processing temperature T = 1600ºC for some d-group transition elements (Ti; Zr, V, Nb, Mo, W) starting from 1.5G/M (graphite/metal powder mixture with mole ratio 1.5:1) compact to ensure co-presence of free carbon with the reaction product. Clear X-ray diffraction (XRD) evidence of for...
Synthesizing higher nitride of molybdenum (Mo) and iron (Fe) in ammonia (NH3) g...
Shohoji, Nobumitsu; Oliveira, F. A. Costa; Fernandes, Jorge Cruz; Rosa, Luís Guerra; Rodriguez, José; Canadas, Immaculada; Ramos, CarlosFlowing gaseous ammonia NH3 with suppressed extent of dissociation (un-cracked NH3) is acknowledged to function as a powerful nitriding medium to realize formation of metal nitride MNx with considerably high N/M ratio x that cannot be achieved through reaction of M with N2 gas. For example, mono-nitride d-MoN of Mo and e-FeNx phase of Fe with x = 0.33 ˜ 0.50 (i. e. hypo-stoichiometric sub-nitride e-Fe2N) were r...
Heterogeneity along the Height in Disc Specimens of Graphite/Tungsten Powder Mi...
Shohoji, Nobumitsu; Magalhães, Teresa; Oliveira, F. A. Costa; Rosa, Luís Guerra; Fernandes, Jorge Cruz; Rodriguez, José; Canadas, ImmaculadaCompositional heterogeneity along the thickness of compacted disc specimens of graphite/tungsten powder mixtures with substoichiometric carbon atom ratios (0.35, 0.50 and 1.00) heated by concentrated solar beam to 1600 C was characterised by X-ray diffraction. Top surface of any examined test piece was consisted purely of mono-carbide WC while the bottom surface showed different constitution depending on the ne...
Mechanical properties of dense cordierite discs sintered by solar radiation hea...
Oliveira, F. A. Costa; Shohoji, Nobumitsu; Martinez, Diego; Fernandes, Jorge Cruz; Rodriguez, José; Rosa, Luís Guerra; Canadas, ImmaculadaConsolidation of cordierite disc specimens was undertaken under concentrated solar beam in a solar furnace at PSA (Plataforma Solar de Almerıá). Satisfactory extent of densification was achieved by the present solar-sintering experiment. The mechanical properties measured for the solar-sintered cordierite test pieces were; density ¼ 2:45 0:02 g/cm3, Vickers microhardness HV ¼ 7:31 0:29 GPa, Young’s modulu...
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