Síntese da liga de FeCo encapsulada em filamentos de carbono com elevada estabilidade química a partir da desidrogenação do etilbenzeno
The catalytic dehydrogenation of ethylbenzene was used to study the nature of deposited carbon and to verify the formation of organized structures in the form of FeCo magnetic alloys encapsulated in carbon filaments via chemical vapor deposition (CVD). The reducing environment from the dehydrogen...
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| المؤلف الرئيسي: | |
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| مؤلفون آخرون: | |
| التنسيق: | Dissertação |
| اللغة: | por |
| منشور في: |
Brasil
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| الموضوعات: | |
| الوصول للمادة أونلاين: | https://repositorio.ufrn.br/jspui/handle/123456789/25934 |
| الوسوم: |
إضافة وسم
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| الملخص: | The catalytic dehydrogenation of ethylbenzene was used to study the nature
of deposited carbon and to verify the formation of organized structures in the form
of FeCo magnetic alloys encapsulated in carbon filaments via chemical vapor
deposition (CVD). The reducing environment from the dehydrogenation (H2
generated in situ) was used to synthesize an FeCo alloy from the metal oxide. The
program is organized in four different temperatures (700, 650, 600 and 550 °C), in
the times of 2h and 4h. X-ray diffraction (XRD), programmed temperature reduction
(TPR), thermogravimetric analysis (TGA), scanning electron microscopy (FEGMEV)
and X-ray dispersive energy (EDS) were characterized. , vibration sample
magnitude (VSM), Raman, transmission electron microscopy (TEM) and gas phase
(GC) chromatography. The diffractograms indicate an FeCo alloy formation and a
presence of crystalline carbon. The H2-TPR profiles confirm that the alloy can be
formed at the reaction temperature from 370 °C. Since the images elaborated by
FEG-SEM and TEM indicated a formation of carbon filaments and a FeCo alloy
favor the growth of the carbon structurally organized. The images also confirm that
the alloy encapsulates the force against the acid. The ratio of the Raman D and G
bands confirms that carbon growth on an FeCo alloy is favored at higher
temperatures. Chromatograms indicate that the filaments were formed from the
methane and/or ethene generated in situ in the reaction, which were seen were not
identified. The magnetic properties were confirmed by the VSM, a variable
according to the reaction time and temperature. The saturation magnetization of a
direct relationship with the crystallite size of the alloy. |
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