Nano Archive

Silica coating of Co-Pt alloy nanoparticles prepared in the presence of poly(vinylpyrrolidone)

Kobayashi, Yoshio and Kakinuma, Hidekazu and Nagao, Daisuke and Ando, Yasuo and Miyazaki, Terunobu and Konno, Mikio (2009) Silica coating of Co-Pt alloy nanoparticles prepared in the presence of poly(vinylpyrrolidone). Journal of Nanoparticle Research, 11 (7). pp. 1787-1794. ISSN 1388-0764 (Print) 1572-896X (Online)

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Official URL: http://www.springerlink.com/content/58603006l6h316...

Abstract

This article describes a method for silica coating of Co–Pt alloy nanoparticles prepared in the presence of poly(vinylpyrrolidone) (PVP) as a stabilizer. The Co–Pt nanoparticles were prepared in an aqueous solution at 25–80 °C from CoCl2 (3.0 × 10−4 M), H2PtCl6 (3.0 × 10−4 M), PVP (0–10 g/L), and NaBH4 (4.8 × 10−3–2.4 × 10−2 M). The silica coating was performed for the Co–Pt nanoparticle colloid containing the PVP ([Co] = [Pt] = 3.0 × 10−5 M) at 25 °C in (1/4) (v/v) water/ethanol solution with tetraethoxyorthosilicate (TEOS) (7.2 × 10−5–7.2 × 10−3 M) and ammonia (0.1–1.0 M). Silica particles, which had an average size of 43 nm and contained multiple cores of Co–Pt nanoparticles with a size of ca. 8 nm, were produced at 1.4 × 10−3 M TEOS and 0.5 M ammonia after the preparation of Co–Pt nanoparticles at 80 °C, 5 g/L PVP, and 2.4 × 10−2 M NaBH4. Their core particles were fcc Co–Pt alloy crystallites. Their saturation magnetization was 2.0-emu/g sample, and their coercive field was 12 Oe.

Item Type:Article
Uncontrolled Keywords:Particle - Alloy - Co–Pt - Poly(vinylpyrrolidone) - Silica - Core-shell - Sol–gel - Magnetic media - Storage
Subjects:Physical Science > Nanophysics
Physical Science > Nanomagnetics
ID Code:7712
Deposited By:Lesley Tobin
Deposited On:04 Dec 2009 14:16
Last Modified:04 Dec 2009 14:16

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