Boron-Assisted Transformation to Rod-Like Graphitic Carbons from Multi-Walled Carbon Nanotubes in Boron-Mixed Multi-Walled Carbon Nanotube Solids

Autor:	Toshiyuki Hashida, Kazuaki Wagatsuma, Mikio Ishikuro, Hikaru Nishizaka, Hisamichi Kimura, Kazuyuki Tohji, Kenichi Motomiya, Go Yamamoto, Yoshinori Sato, Akira Okubo
Rok vydání:	2011
Předmět:	Nanotube Materials science Scanning electron microscope chemistry.chemical_element Carbon nanotube Boron carbide Atmospheric temperature range Conductivity law.invention chemistry.chemical_compound chemistry law General Materials Science Composite material Spectroscopy Boron
Zdroj:	ACS Applied Materials & Interfaces. 3:2431-2439
ISSN:	1944-8252 1944-8244
DOI:	10.1021/am200335n
Popis:	We produced boron-mixed multi-walled carbon nanotube solids (B-mixed MWCNT solids) by heating and pressing the powder of purified MWCNTs mixed with 1, 5, and 10 wt % boron in the temperature range 1400-1800 °C every 200 °C under a constant pressure of 20 MPa in vacuo, and investigated the influence of boron addition on nanotube structure and the mechanical and electrical properties of the resulting B-mixed MWCNT solids. The structure of the prepared material was characterized by scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy-electron energy loss spectroscopy, Raman scattering spectroscopy, and X-ray diffraction, and their mechanical properties and conductivity were measured using a mechanical and Vickers indentation tester and an electric resistor, respectively. It is notable that part of the nanotubes in the B-mixed MWCNT solids solidified at 1800 °C had dramatically changed into rod-like graphitic carbons (RLGCs). The occupancy distribution of RLGCs increased with increasing boron contents. However, boron was not detected in the energy-loss near-edge structure spectrum of RLGCs. Furthermore, RLGCs were not observed in the boron-unmixed sample treated with the same solidified condition, indicating that adding boron causes a remarkable ability to transform the phase of MWCNT. Transformation from MWCNTs to RLGCs resulted in increased specific bending strength and modulus, Vickers hardness, and electrical conductivity of B-mixed MWCNT solids with increasing boron content and solidified temperature.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::60eb2d66c8985c4a974561f21032f3e4 https://doi.org/10.1021/am200335n Zobrazit plný text záznamu