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Erzeugung von hoch nitridhaltigen Molybdän‐ und Eisennitriden in einem Ammoniumgasvolumenstrom bei Bestrahlung durch konzentrierte Solarstrahlen in einer solaren Brennkammer
Author(s) -
Shohoji N.,
Almeida Costa Oliveira F.,
Cruz Fernandes J.,
Guerra Rosa L.,
Rodríguez Garcia J.,
Canadas Martínez I.,
Ramos Miñarro C.,
Magalhães T.,
Cestari F.
Publication year - 2013
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201300163
Subject(s) - nitride , nitriding , molybdenum , irradiation , stoichiometry , analytical chemistry (journal) , chemistry , ammonia , nitrogen , oxygen , dissociation (chemistry) , solar furnace , materials science , inorganic chemistry , solar energy , layer (electronics) , physics , organic chemistry , chromatography , nuclear physics , ecology , biology
Abstract Flowing gaseous ammonia NH 3 with suppressed extent of dissociation (un‐cracked NH 3 ) is acknowledged to function as a powerful nitriding medium to realize formation of metal nitride MN x with considerably high N/M ratio x that cannot be achieved through reaction of M with N 2 gas. For example, mono‐nitride δ‐MoN of Mo and ε‐FeN x phase of Fe with x = 0.33 ˜ 0.50 (i. e. hypo‐stoichiometric sub‐nitride ε‐Fe 2 N) were reported to be difficult to prepare in N 2 gas environment even at elevated pressure but might be synthesized in flowing NH 3 gas at normal pressure when reaction temperature and NH 3 gas flow rate were set adequately. In the present work, nitriding experiments for Mo and Fe were carried out in flowing NH 3 gas under irradiation with concentrated solar beam. The acquired experimental evidences demonstrated that temperature range for formation of δ‐MoN was somewhat extended in flowing NH 3 gas under heating with concentrated solar beam compared with that under heating in conventional laboratory or industrial electric furnace. On the other hand, no such merit of extending temperature range for formation of ε‐Fe 2 N in flowing NH 3 gas was detected in the present work under heating with concentrated solar beam.