Effects of Fe/Si Stoichiometry on Formation of Fe<sub>3</sub>Si/FeSi-Al<sub>2</sub>O<sub>3</sub> Composites by Aluminothermic Combustion Synthesis
Aluminothermic combustion synthesis was conducted with Fe<sub>2</sub>O<sub>3</sub>–Al–Fe–Si reaction systems under Fe/Si stoichiometry from Fe-20 to Fe-50 at. % Si to investigate the formation Fe<sub>3</sub>Si/FeSi–Al<sub>2</sub>O<sub>3</sub&g...
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| Main Authors: | , , |
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| Format: | article |
| Language: | EN |
| Published: |
MDPI AG
2021
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| Subjects: | |
| Online Access: | https://doaj.org/article/108437ef68224d868b3d5135a3fb604f |
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| Summary: | Aluminothermic combustion synthesis was conducted with Fe<sub>2</sub>O<sub>3</sub>–Al–Fe–Si reaction systems under Fe/Si stoichiometry from Fe-20 to Fe-50 at. % Si to investigate the formation Fe<sub>3</sub>Si/FeSi–Al<sub>2</sub>O<sub>3</sub> composites. The solid-state combustion was sufficiently exothermic to sustain the overall reaction in the mode of self-propagating high-temperature synthesis (SHS). Dependence of iron silicide phases formed from SHS on Fe/Si stoichiometry was examined. Experimental evidence indicated that combustion exothermicity and flame-front velocity were affected by the Si percentage. According to the X-ray diffraction (XRD) analysis, Fe<sub>3</sub>Si–Al<sub>2</sub>O<sub>3</sub> composites were synthesized from the reaction systems with Fe-20 and Fe-25 at.% Si. The increase of Si content led to the formation of both Fe<sub>3</sub>Si and FeSi in the final products of Fe-33.3 and Fe-40 at.% Si reaction systems, and the content of FeSi increased with Si percentage. Further increase of Si to Fe-50 at.% Si produced the FeSi–Al<sub>2</sub>O<sub>3</sub> composite. Scanning electron microscopy (SEM) images revealed that the fracture surface morphology of the products featured micron-sized and nearly spherical Fe<sub>3</sub>Si and FeSi particles distributing over the dense and connecting substrate formed by Al<sub>2</sub>O<sub>3</sub>. |
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