Iron-carbon composite nanopowders have been synthesized by the CO₂ laser pyrolysis of gas-phase reactants. The experimental device allows for a very low reaction time and a rapid freezing that creates nanoscale-condensed particles. Iron pentacarbonyl and ethylene-acetylene mixtures were used as iron and carbon precursors. In a two-steps experiment, the reaction products may present themselves as iron-based nanoparticles dispersed in a carbon matrix. By a careful control of experimental parameters and radiation geometries we demonstrate the feasibility of an efficient and well-controlled, single-step technique for the production of iron-based nano-cores embedded in carbon layers. Highly dispersed nanoparticles, narrow size distributions and particles with about 4.5 - 6 nm mean diameters were obtained. Electron microscopy and Raman spectroscopy were used in order to analyze the structure and composition of the obtained nanopowders as well as their Soxhlet residue.

Iron pentacarbonyl

Acetylene

Carbon fibers

10.1117/12.501664

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Citations (3)

Iron/iron oxides core–shell nanoparticles by laser pyrolysis: Structural characterization and enhanced particle dispersion

Applied Surface Science (2007)

E. Popovici Florian Dumitrache I. Morjan R. Alexandrescu V. Ciupină

Iron oxide nanoparticles

Particle (ecology)

10.1016/j.apsusc.2007.09.022

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Citations (33)

Hanging colloidal drop: A new photonic crystal synthesis route

Photonics and Nanostructures - Fundamentals and Applications (2018)

I. Sandu Marius Dumitru C. Fleaca Florian Dumitrache

Colloidal crystal

Polystyrene

Pillar

10.1016/j.photonics.2018.02.001

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Citations (15)

Fabrication and Electric Transport in MgB<sub>2</sub> Doped with Nanosized Carbon-Based Core-Shell Structures

Materials science forum (2010)

V. Sandu G. Aldica S. Popa E. Cimpoiasu Florian Dumitrache

We present the fabrication and electric properties of MgB2 ceramic samples doped with nanosized spheres, 4-8 nm, of graphite with a metallic core. The samples were prepared using the spark plasma sintering technique. The size of the additive is comparable to the superconducting coherence length. The short processing time limits the diffusion of the carbon while keeping the core intact. Therefore, in addition to the doping with carbon, the metallic core, which has the size smaller than the superconducting coherence length, create pinning centers which might improve the dissipationless electric transport. The results are analyzed in the framework of different pinning models.

Spark Plasma Sintering

Carbon fibers

10.4028/www.scientific.net/msf.663-665.871

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Citations (1)

Carbon nanostructures from Fe–C nanocomposites by activated CVD methods

Physica status solidi. C, Conferences and critical reviews/Physica status solidi. C, Current topics in solid state physics (2010)

C. Fleaca I. Morjan R. Alexandrescu Florian Dumitrache Iuliana Soare

Abstract Iron‐based core‐shell nanoparticles can present interesting catalytic properties for the growth of carbon nanostructures. We report the synthesis of various carbon nanostructures using activated chemical vapour deposition methods. These structures were analysed by Scanning Electon Microscopy (SEM) and Raman spectroscopy. Laser pyrolysis technique was used for synthesis of less than 10 nm diameter Fe‐C core‐shell catalyst nanoparticles. Acetone suspensions of Fe‐C nanoparticles were drop‐casted or spin coated onto Si(100) substrates. The consequence of hydrogen selective etching of these nanocomposites at 550 °C, followed by a treatment with a mixture of H 2 and C 2 H 2 at 700 °C (both in the presence of hot filaments) was the growth of corrugated ribbons and decorated or distorted carbon nanotubes/nanofibers. Round agglomerate nanoparticles and long and very thin nanotubes were observed on the substrates edges (protected from direct etching). By adding in similar conditions a glow discharge plasma to hot filaments, the resulted deposits contain oriented nanotubes. Due to the implication of the electric field, the presence of both plasma and hot wires seems to significantly change the specific growth conditions of carbon nanostructures towards those resulted when only incandescent filaments were used (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

10.1002/pssc.200982975

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The study of nitrogen inclusion in carbon nanotubes obtained by catalytic laser-induced chemical vapour deposition (C-LCVD)

Applied Surface Science (2017)

I. Morjan I. Morjan Alina Ilie M. Scarisoreanu Lucian Gavrilă

Carbon fibers

Acetylene

10.1016/j.apsusc.2017.06.296

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Citations (11)