Jeonju, South Korea
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So K.P.,Sungkyunkwan University | Kim E.S.,Sungkyunkwan University | Biswas C.,Sungkyunkwan University | Jeong H.Y.,Sungkyunkwan University | And 3 more authors.
Scripta Materialia | Year: 2012

Disintegration of carbon nanotubes (CNTs) into C atoms and dissolution into Al nanoparticles is achieved by mechanically grinding two materials together. This low-temperature solid-state dissolution process involves several steps: (i) mixing CNTs with Al particles; (ii) Al nanoparticle formation; (iii) disintegration of CNTs into C atoms; and (iv) embedding of C atoms into Al nanoparticles. C atom are embedded into Al nanoparticles up to a level of ∼50 wt.% via the formation of an amorphous phase. This enhances hardness by more than 50%. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

So K.P.,Sungkyunkwan Advanced Institute of Nanotechnology | So K.P.,Chonju Machinery Research Center | Lee I.H.,Sungkyunkwan Advanced Institute of Nanotechnology | Lee I.H.,Chonju Machinery Research Center | And 9 more authors.
Acta Materialia | Year: 2011

The wetting of a metal on carbon nanotubes is fundamentally difficult due to the unusually large difference between their surface tensions and is a bottleneck for making metal-carbon nanotube (CNT) composites. Here, we report a simple method to enhance the wettability of metal particles on the CNT surface by applying aluminum, which is the material with the largest surface tension. This method involves two steps: (i) Al nanoparticles are decorated on multiwalled carbon nanotubes by electroplating and (ii) Al powder is further spread on Al-electroplated CNTs, followed by high-temperature annealing to accommodate complete wetting of the aluminum. The large surface tension difference is overcome by forming strong AlC covalent bonds initiated by defects of the CNTs. The decrease in the D-band intensity, the G-band shift in the Raman spectroscopy and the formation of AlC covalent bonds, as confirmed by X-ray photoelectron spectroscopy, were in agreement with our structural model of CNTvacancyOAl determined by density functional calculations. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

So K.P.,Sungkyunkwan Advanced Institute of Nanotechnology | Biswas C.,Sungkyunkwan Advanced Institute of Nanotechnology | Lim S.C.,Sungkyunkwan Advanced Institute of Nanotechnology | An K.H.,Chonju Machinery Research Center | Lee Y.H.,Sungkyunkwan Advanced Institute of Nanotechnology
Synthetic Metals | Year: 2011

We focus on the formation of strong aluminum (Al)-carbon nanotube (CNT) covalent bonds on the CNT walls without deteriorating CNTs for mechanically strong composite. We propose a simple electroplating method to realize Al-CNT covalent bonds on the CNT wall. The CNT electrode was formed on the Cu collector as a cathode and separated from the anode by an organic separator in tetrahydrofuran (THF) under Ar atmosphere. The Al deposition started to increase rapidly at above Al reduction potential. The formation of Al-C covalent bonds was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Charge transfer from CNTs to Al and generation of D-bands in Raman spectroscopy further confirmed the formation of Al-C covalent bonds. © 2010 Published by Elsevier B.V. All rights reserved.

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