Synthesis and Magnetic Properties of Ni and Carbon Coated Ni by Levitational Gas Condensation (LGC)

Young Rang Uhm,Chang Kyu Rhee

doi:10.1155/2013/427489

Young Rang Uhm, Chang Kyu Rhee

Open Access

https://doi.org/10.1155/2013/427489

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Abstract

The nickel (Ni), and carbon coated nickel (Ni@C) nanoparticles were synthesized by levitaional gas condensation (LGC) methods using a micron powder feeding (MPF) system. Both metal and carbon coated metal nano powders include a magnetic ordered phase. The synthesis by LGC yields spherical particles with a large coercivity. The abnormal initial magnetization curve for Ni indicates a non-collinear magnetic structure between the core and surface layer of the particles. The carbon coated particles had a core structure diameter at and below 10 nm and were covered by 2-3 nm thin carbon layers. The hysteresis loop of the as-prepared Ni@Cs materials with unsaturated magnetization shows a superparamagnetic state at room temperature.

Highlights

Nanoparticles have achieved significant attention owing to the novel electro-optic, magnetic, and catalytic properties that arise from the quantum size effect and large specific surface areas that are characteristic of nanosized species [1, 2]
High purity Ni and Ni@C nanopowders were synthesized by a levitaional gas condensation (LGC) method using a micron powder feeding (MPF) system Journal of Nanomaterials
The induction heat coil and the concept of LGC system are displayed at Figure 1

Summary

Introduction

Nanoparticles have achieved significant attention owing to the novel electro-optic, magnetic, and catalytic properties that arise from the quantum size effect and large specific surface areas that are characteristic of nanosized species [1, 2]. Agglomeration of the particles in a solvent is a serious problem when preparing nanofluids. To overcome these problems, a protective shell has been recommended to improve the chemical stability of metal nanoparticles and the dispersion stability in the solvent [4,5,6]. A graphitic carbon shell is regarded as an ideal coating as it is light and shows high stability in both chemical and physical environments [8, 9]. The preparation of a stable suspension of metallic nanoparticles is difficult owing to the high density and agglomeration of particles. We report on the dispersion stability in various solutions, such as water, ethanol, and ethylene glycol

Experiment

Results and Discussion

Conclusions