Reaction chemistry in the Mg–B2O3–MoO3 system reactive mixtures

Fundamental aspects of reaction path in the MoO3+B2O3+Mg system to synthesize molybdenum boride have been investigated. The phase transformation and structural evaluation were studied by means of differential thermal analysis (DTA) techniques, X-ray diffractometry (XRD), scanning electron microscopy...

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Bibliographic Details
Published in:International journal of refractory metals & hard materials 2015-01, Vol.48, p.102-107
Main Authors: Torabi, Omid, Ebrahimi-Kahrizsangi, Reza, Golabgir, Mohammad Hossein, Tajizadegan, Hamid, Jamshidi, Amin
Format: Article
Language:English
Subjects:
Borides
Differential thermal analysis
Diffraction
Exothermic reactions
Magnesiothermic reaction
Magnesium
Mechanochemical processing
MgO
Molybdenum
Molybdenum boride
Nanocomposites
Scanning electron microscopy
Transmission electron microscopy
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Summary:Fundamental aspects of reaction path in the MoO3+B2O3+Mg system to synthesize molybdenum boride have been investigated. The phase transformation and structural evaluation were studied by means of differential thermal analysis (DTA) techniques, X-ray diffractometry (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Thermodynamic evaluations indicated that the reaction was highly exothermic and should be a mechanically induced self-sustaining reaction (MSR). According to DTA results, for unmilled sample, the reaction's sequence includes the following reactions: MoO3 reduction→B2O3 reduction→molybdenum boride formation. For 3h-milled sample, the temperature of exothermic reaction decreased significantly and all the reactions occurred, simultaneously. Based on XRD results, the mechanochemical products including MgO and mix of molybdenum boride phases were achieved after 4h of high energy ball milling. SEM and TEM observations confirmed that the range of particle size was within 100nm. •Molybdenum boride has been synthesized starting with Mg, MoO3 and B2O3.•MSR mode reaction took place after 4h milling time.•By increasing milling time, an exothermic reaction occurs before magnesium melting.•Nano-scale reinforcement was obtained by mechanochemical technique.
ISSN:0263-4368
2213-3917
DOI:10.1016/j.ijrmhm.2014.07.040