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Thermal diffusivity of aligned multi‐walled carbon nanotubes measured by the flash method
Author(s) -
Mäklin Jani,
Halonen Niina,
Toth Géza,
Sápi András,
Kukovecz Ákos,
Kónya Zoltán,
Jantunen Heli,
Mikkola JyriPekka,
Kordas Krisztián
Publication year - 2011
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201100143
Subject(s) - thermal diffusivity , carbon nanotube , materials science , chemical vapor deposition , annealing (glass) , laser flash analysis , atmospheric temperature range , phonon , phonon scattering , composite material , thermal , amorphous solid , analytical chemistry (journal) , thermodynamics , nanotechnology , thermal conductivity , condensed matter physics , chemistry , crystallography , physics , chromatography
Thermal diffusivity of freestanding catalytic chemical vapor deposition (CCVD) grown multi‐walled carbon nanotube (MWCNT) forests (height of 1.5 and 1.9 mm) was characterized in the temperature range between 25 and 200 °C. Copper and Al‐alloy metal blocks were used as references for validation of the experimental setup. The measurements were carried out along the MWCNT alignment direction with a thermal property analyzer that uses the flash method. The thermal diffusivities measured at room temperature for as‐grown and post‐annealed (2 h at 480 °C in open air) samples were found to be ∼0.45 and ∼0.23 cm 2 /s, respectively. In both cases, the thermal diffusivity values were slightly decreasing with increasing temperature. The observed decrease in diffusivity after annealing is most probably due to the loss of amorphous carbon in the specimens and also because of the increased defect density in the nanotube walls resulting in a more pronounced phonon scattering in the lattice. The measured thermal diffusivities for as‐grown samples agree with data reported elsewhere for similar MWCNT materials [W. Yi et al., Rev. B 59 , 9015 (1999) and T. Borca‐Tasciuc et al., J. Appl. Phys. 98 , 054309 (2005)].