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Title: Characterization of ultralow thermal conductivity in anisotropic pyrolytic carbon coating for thermal management applications

Abstract

Pyrolytic carbon (PyC) is an important material used in many applications including thermal management of electronic devices and structural stability of ceramic composites. Accurate measurement of physical properties of structures containing textured PyC layers with few-micrometer thickness poses new challenges. Here a laser-based thermoreflectance technique is used to measure thermal conductivity in a 30-μm-thick textured PyC layer deposited using chemical vapor deposition on the surface of spherical zirconia particles. Raman spectroscopy is used to confirm the graphitic nature and characterize microstructure of the deposited layer. Room temperature radial and circumferential thermal conductivities are found to be 0.28 W m –1 K –1 and 11.5 W m –1 K –1, corresponding to cross-plane and in-plane conductivities of graphite. While the anisotropic ratio of the in-plane to cross-plane conductivities is smaller than previous results, the magnitude of the smallest conductivity is noticeably smaller than previously reported values for carbon materials and offers opportunities in thermal management applications. Very low in-plane and cross-plane thermal conductivities are attributed to strong grain boundary scattering, high defect concentration, and small inter-laminar porosity. Lastly, experimental results agree with the prediction of thermal transport model informed by the microstructure information revealed by Raman spectroscopy.

Authors:
ORCiD logo [1];  [2];  [3]; ORCiD logo [3]; ORCiD logo [3]; ORCiD logo [3]; ORCiD logo [3]; ORCiD logo [3];  [4]; ORCiD logo [4]; ORCiD logo [1]
  1. The Ohio State Univ., Columbus, OH (United States)
  2. Idaho National Lab. (INL), Idaho Falls, ID (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Iowa State Univ., Ames, IA (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1415411
Report Number(s):
LA-UR-17-25392
Journal ID: ISSN 0008-6223
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Carbon
Additional Journal Information:
Journal Volume: 129; Journal Issue: C; Journal ID: ISSN 0008-6223
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Wang, Yuzhou, Hurley, David H., Luther, Erik Paul, Beaux, II, Miles Frank, Vodnik, Douglas R., Peterson, Reuben James, Bennett, Bryan L., Usov, Igor Olegovich, Yuan, Pengyu, Wang, Xinwei, and Khafizov, Marat. Characterization of ultralow thermal conductivity in anisotropic pyrolytic carbon coating for thermal management applications. United States: N. p., 2017. Web. doi:10.1016/j.carbon.2017.12.041.
Wang, Yuzhou, Hurley, David H., Luther, Erik Paul, Beaux, II, Miles Frank, Vodnik, Douglas R., Peterson, Reuben James, Bennett, Bryan L., Usov, Igor Olegovich, Yuan, Pengyu, Wang, Xinwei, & Khafizov, Marat. Characterization of ultralow thermal conductivity in anisotropic pyrolytic carbon coating for thermal management applications. United States. doi:10.1016/j.carbon.2017.12.041.
Wang, Yuzhou, Hurley, David H., Luther, Erik Paul, Beaux, II, Miles Frank, Vodnik, Douglas R., Peterson, Reuben James, Bennett, Bryan L., Usov, Igor Olegovich, Yuan, Pengyu, Wang, Xinwei, and Khafizov, Marat. 2017. "Characterization of ultralow thermal conductivity in anisotropic pyrolytic carbon coating for thermal management applications". United States. doi:10.1016/j.carbon.2017.12.041.
@article{osti_1415411,
title = {Characterization of ultralow thermal conductivity in anisotropic pyrolytic carbon coating for thermal management applications},
author = {Wang, Yuzhou and Hurley, David H. and Luther, Erik Paul and Beaux, II, Miles Frank and Vodnik, Douglas R. and Peterson, Reuben James and Bennett, Bryan L. and Usov, Igor Olegovich and Yuan, Pengyu and Wang, Xinwei and Khafizov, Marat},
abstractNote = {Pyrolytic carbon (PyC) is an important material used in many applications including thermal management of electronic devices and structural stability of ceramic composites. Accurate measurement of physical properties of structures containing textured PyC layers with few-micrometer thickness poses new challenges. Here a laser-based thermoreflectance technique is used to measure thermal conductivity in a 30-μm-thick textured PyC layer deposited using chemical vapor deposition on the surface of spherical zirconia particles. Raman spectroscopy is used to confirm the graphitic nature and characterize microstructure of the deposited layer. Room temperature radial and circumferential thermal conductivities are found to be 0.28 W m–1 K–1 and 11.5 W m–1 K–1, corresponding to cross-plane and in-plane conductivities of graphite. While the anisotropic ratio of the in-plane to cross-plane conductivities is smaller than previous results, the magnitude of the smallest conductivity is noticeably smaller than previously reported values for carbon materials and offers opportunities in thermal management applications. Very low in-plane and cross-plane thermal conductivities are attributed to strong grain boundary scattering, high defect concentration, and small inter-laminar porosity. Lastly, experimental results agree with the prediction of thermal transport model informed by the microstructure information revealed by Raman spectroscopy.},
doi = {10.1016/j.carbon.2017.12.041},
journal = {Carbon},
number = C,
volume = 129,
place = {United States},
year = 2017,
month =
}

Journal Article:
Free Publicly Available Full Text
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  • A method was developed for the determination of the thermal conductivities of anisotropic solids under conditions of two-dimensional, steady- state heat conduction in a cylinder of finite length heated in vacuum by high- frequency induction and radiating heat to the surroundings. The method was used to determine the radial thermal conductivity, k r, and the axial thermal conductivity, k z, of molded ZT-type and pyrolytic graphite in the temperature range 1260 to 2200 deg K. For ZT-type graphite, k z/k r =-- 0.101 + 2.002 x 10 -4 x T (1260 deg K < T < 2200 deg K); formore » pyrolytic graphite, k z/k r = 0.0376 at 1817 deg K.« less
  • Highlights: • Carbon nanoflakes doped with nitrogen were produced by a pyrolytic technique. • Quarternary, pyrrolic and pyridinic types of nitrogen are confirmed by XPS. • Nitrogen content depends on precursor used and temperature processed. • Specific surface area values decrease with increasing of synthesis duration. • N-doped carbon nanoflakes may be suitable for electrochemical applications. - Abstract: Nitrogen doped carbon nanoflakes, which are very important for many electrochemical applications, were synthesized by pyrolysis of nitrogen containing organic compounds over metal oxide template. Acetonitrile, pyridine and butylamine, which are of different volatility were tested as N-containing precursors. Morphology, structure andmore » chemical composition of the as-synthesized materials were investigated by scanning electron microscopy (SEM), high resolution transmission electron microscopy (TEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that materials are highly defective and consist of a few malformed graphene layers. X-ray photoelectron spectra reflect the dominant graphitic and pyridinic N-bonding configuration. It was also noted that specific surface area depends on the duration and temperature of the reaction. Increase in duration and temperature led to decrease of the specific surface area from 1000 to 160 m{sup 2}/g, 1170 to 210 m{sup 2}/g and 1180 to 480 m{sup 2}/g for acetonitrile, butylamine and pyridine precursors, respectively.« less