Microstructures and magnetic properties of boron nitride- and carbon-coated iron nanoparticles synthesized by a solid phase reaction

Abstract

A promising technique to synthesize iron nanoparticles with boron nitride (BN) and carbon (C) nanocoatings was developed. Mixtures of a-Fe 2 O 3 and boron or carbon powders were employed as starting materials and were annealed at temperatures above 1273 K in a nitrogen atmosphere. Products were mainly composed of a-Fe and hexagonal BN or graphite carbon without hematite, which was confirmed by X-ray diffraction. High-resolution transmission electron microscope observation revealed that BN and C nanocapsules with iron nanoparticles of ca. 300 nm in diameter were formed, and they exhibited soft magnetic properties from magnetization measurements. In addition, multi-walled BN and C nanotubes with diameters of a few hundred nanometers were produced by the present method.

The growth of carbon coating layers on iron particles and the effect of alloying the iron with silicon

“…The C-encapsulated Fe particles were synthesized by arc discharge methods [11,12]. We have also developed an adequate method for mass-production so as to fabricate Fe fine particles encapsulated by C layers through the carbothermic reduction of iron oxide powders [13]. All these metallic particles were successfully coated, however, the mechanism of the coating was not studied in detail.…”

Preparation and characterization of Gd2O3:Eu3+ luminescence nanotubes

“…Rare earth oxides are a kind of advanced materials and have been widely used as high performance luminescent devices, magnets, catalysts and other functional materials [6,7]. Some rare earth (Er, Tm, Yb, Lu, Dy, Ho, Y, Tb) oxide nanotubes have been successfully fabricated by several methods, such as template-assisted method and hydrothermal method [8][9][10][11].…”

Fe fine particles encapsulated by titanium oxides with high magnetization for biomedical application

“…We have developed a simple procedure to fabricate Fe and Co fine particles encapsulated by C layers [10,11]. Developing this procedure, synthesis of Fe fine particles encapsulated not by C, but by titanium oxide has been tried because titanium oxides are known to show chemical stability and biocompatibility [12].…”