Proceedings of the 7th World Congress on Mechanical, Chemical, and Material Engineering (MCM'21)
Prague, Czech Republic Virtual Conference – August, 2021
Paper No. MMME 110
DOI: 10.11159/mmme21.110

Optimization of CVD Parameters during Synthesis of Fe@C CoreShell Nanoparticles using Fe-Nitrate Based Precursors
Sıddıka Mertdinç1, Umut Savacı2, M. Lütfi Öveçoğlu1, Duygu Ağaoğulları1
1

Istanbul Technical University, Chemical and Metallurgical Engineering Faculty, Metallurgical and Materials Engineering
Department, Particulate Materials Laboratories (PML), 34469, Istanbul, Turkey
mertdinc@itu.edu.tr; ovecoglu@itu.edu.tr; bozkurtdu@itu.edu.tr
2Eskisehir Technical University, Faculty of Engineering, Department of Materials Science and Engineering, Iki Eylul Campus, 26555,
Tepebasi, Eskisehir, Turkey
umutsavaci@eskisehir.edu.tr

Extended Abstract
Magnetic iron nanoparticles are desired materials for various engineering applications in electronic and biomedical
industries due to their soft ferromagnetic properties [1,2]. Hyperthermia, magnetic resonance imaging, drug and genedelivery are some examples of the potential biomedical applications of the magnetic iron nanoparticles [3,4]. Even though
they have superior magnetic properties; they are not resistant to corrosion. Thus, core/shell nanoparticles have beendeveloped to protect the magnetic core materials [5]. In general, carbon encapsulated magnetic nanoparticles are preferred
for biomedical practice. Carbon based coatings provide large surface area, corrosion protection and energy storage. For thisreason, they are desired shell materials for magnetic nanoparticles [2,3,6]. Various forms of carbon based shell are locatedon the magnetic nanoparticles like amorphous shell, graphene shell and graphite shell [6]. Carbon encapsulated Fe
nanoparticles have been synthesized using different processes such as chemical vapor deposition (CVD), combustion
synthesis and hydrothermal synthesis [7]. Amongst them, the CVD process increases the gas and powder interaction which
accelerates the decomposition reactions for graphitic shell formations on the core particles [3].
In this study, precursor powders of the CVD system were Fe-nitrate (Fe(NO3)3.9H2O) salts mixed with fumed silica
powders in ethanol to prepare Fe nitrate loaded fumed silica powders followed by placing them inside a furnace in quartz
boats (~200 mg). Hydrogen (H2) and methane (CH4) were used as flowing gases in the CVD system. H2 was used for thereduction of Fe(NO3)3.9H2O to Fe and the decomposition of CH4 led to graphitic layer formation on the Fe nanoparticles.
The CVD system used in this investigation consists of a tube furnace, a vacuum pump and gas flowmeters. Two different
CVD temperatures (900 and 950°C) up to a dwell time of 90 min and two different CH4 flow rates (100 ml/min and 200ml/min) at a constant H2 flow rate (100 ml/min) were employed. After that, leaching with 2 M HF and 4 M HCl acidsolutions were performed for the purification of powders. Fumed silica was removed with HF leaching and uncoated Fe
nanoparticles were removed with HCl acid leaching. X-Ray diffractometry (XRD), Raman analysis, Scanning electronmicroscope (SEM), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM) were used in thecharacterization of the synthesized powders. Raman and XRD investigations revealed that 950°C was not a suitabletemperature for graphitic layer formations it causes excessive carbon decomposition. Therefore, 900°C is chosen as theoptimum CVD temperature and other experiments were carried out at this temperature. TEM images reveal that the 900°C
synthesized powders had core sizes varying in size between 15-40 nm and shell sizes between 3-13 nm. VSM results
showed that Fe@C nanoparticles had soft ferromagnetic behavior with low saturation magnetization and coercivity values
changed between 322.91-587.13 Oe and 23-88 emu/g.

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MMME 110-2