Self-propagating combustion synthesis via an MSR process: An efficient and simple method to prepare (Ti, Zr, Hf)B2–Al2O3 powder nanocomposites

The synthesis of (Ti1−xZrx)B2–Al2O3, (Ti1−xHfx)B2–Al2O3 and (Zr1−xHfx)B2–Al2O3 (x=0, 0.5 and 1) powder nanocomposites via a mechanochemical method using TiO2, ZrO2, HfO2, HBO2 and Al as the raw materials was investigated. The formation of the nanocomposites proceeds via a mechanically-induced self-s...

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Bibliographic Details
Published in:Powder technology 2014-04, Vol.256, p.244-250
Main Authors: Sayagués, M.J., Avilés, M.A., Córdoba, J.M., Gotor, F.J.
Format: Article
Language:English
Subjects:
Applied sciences
Chemical engineering
Combustion
Diborides
Diffraction techniques
Electron microscopy
Exact sciences and technology
Miscellaneous
MSR
Nanocomposites
Sintering, pelletization, granulation
Solid-solid systems
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Summary:The synthesis of (Ti1−xZrx)B2–Al2O3, (Ti1−xHfx)B2–Al2O3 and (Zr1−xHfx)B2–Al2O3 (x=0, 0.5 and 1) powder nanocomposites via a mechanochemical method using TiO2, ZrO2, HfO2, HBO2 and Al as the raw materials was investigated. The formation of the nanocomposites proceeds via a mechanically-induced self-sustaining reaction (MSR) process that involves several simultaneous reactions. The aluminothermic reductions of the TMO2 and HBO2 produce Al2O3 and transition metal and boron elements, which in turn react to yield the diboride phase. The ignition of the complex combustion reaction occurred after a short milling time (15–30min), instantly transforming most of the reactants into products. The sample composition was marked by the stoichiometry of the combustion reaction, and the resulting nanocomposites were analysed using XRD, ED, SEM, TEM and EDX techniques. The X-ray results confirmed the biphasic character of the prepared composite powder (TMB2 and Al2O3 structures); minor amounts of the Zr and Hf oxides were also observed. The achieved microstructure was characterised by the agglomeration of Al2O3 nanocrystallites and diboride crystals with a diffraction domain size ranging between 100 and 300nm. [Display omitted] •(Ti–Zr–Hf)B2/Al2O3 powder nanocomposites were prepared by an efficient method: MSR.•MSR is a very useful process even for a complex system involving several reactions.•Excellent distribution of the diboride/alumina phases in the nanocomposite material•Production of a nanopowder material that will improve the bulk final properties
ISSN:0032-5910
1873-328X
DOI:10.1016/j.powtec.2014.02.031