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Thermal decomposition of δ-MoN and ε-Fe2N synthesized under concentrated solar radiation in NH3 gas stream
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Resumo(s)
ABSTRACT: Decomposition temperatures of δ-MoN and ε-Fe2N synthesized with flowing NH3 gas under concentrated solar radiation heating were evaluated by Differential Scanning Calorimetry (DSC) in Argon (Ar) gas environment. The measured decomposition temperature of δ-MoN and ε-Fe2N were dependent on the solar synthesis conditions, particularly either NH3 or N2 gas flow rate at temperature. Sample containing δ-MoN showed two exothermic peaks around 680 and 900 ◦C, attributed to the reactions of δ-phase into γ-single-phase and (γ+β)-two-phase Mo2N, respectively, attributed to the dissociation reaction of δ-phase into γ-single phase and the dissociation reaction of γ-phase into metallic M saturated with N, respectively. Decomposition of ε-Fe2N took place into γ’-Fe4N in two steps occurring at 606 and 660 ◦C, respectively. When N2 instead of ammonia (NH3) gas was used, complete dissociation of γ’-Fe4N into Fe took place at around 610 ◦C. Full decomposition of γ’-Fe4N into metallic α-Fe(N) was corroborated by X-ray diffraction (XRD) analysis.
Descrição
Palavras-chave
Materials Nitride Thermochemical processes Calorimetry X-ray diffraction
Contexto Educativo
Citação
Canadas, Inmaculada... [et.al.] - Thermal decomposition of δ-MoN and ε-Fe2N synthesized under concentrated solar radiation in NH3 gas stream. In: Thermochimica Acta, 2023, vol. 719, article nº 179394
Editora
Elsevier