Structure and magnetic properties of iron nanoparticles synthesized by chemical vapor condensation

Abstract

Iron nanoparticles were synthesized by chemical vapor condensation (CVC) without the aid of LN 2 chiller. The powder synthesized at 400 °C was a mixture of amorphous and crystalline α-Fe. Fully crystallized iron particles were then obtained at and above 600 °C. When the reactor temperature was 1000 °C, however, nonmagnetic γ-Fe was stabilized together with α-Fe. The synthesized particles, mostly possessing the core-shell type structure, were all nearly spherical, but the average particle size rapidly increased as the temperature increased. The surface layer that enclosed the iron core and became thicker in smaller particles was Fe 3 O 4 or Fe 3 O 4 -related amorphous. Except for the one synthesized at 1000 °C, the iron nanoparticles were not fully saturated. The iron nanoparticles (~20 nm) synthesized at 600 °C exhibited i H c ~ 1.0 kOe and M s ~ 170 emu/g.

Oxidation Kinetics and Magnetic Properties of Elemental Iron Nanoparticles

“…Compared with bulk material, characterizing magnetic properties and oxidation mechanism of Fe MNPs remains challenging. Although there have been intensive investigation on Fe MNPs, most of these studies employed particles with wide size distribution. The measured physical properties were effectively volume‐weighted averages, which tend to be biased by large particles.…”

Synthesis and properties of magnetic fluid based on iron nanoparticles prepared by a vapor-phase condensation process

“…1 without forming big cluster. As shown in the right-hand figure, each particle had a typical core-shell structure: The metal iron core was enclosed with a layer of iron oxide, i.e., Fe 3 O 4 [4].…”

“…Iron nanoparticles were fabricated by chemical vaporcondensation(CVC) process using iron pentacarbonyl (Fe(CO) 5 ) as precursor [3,4]. The liquid precursor was vaporized in evaporator.…”