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

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:
Report Number(s):
LA-UR-17-25392
Journal ID: ISSN 0008-6223
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Carbon
Additional Journal Information:
Journal Volume: 129; Journal Issue: C; Journal ID: ISSN 0008-6223
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1415411

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., 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 = {12}
}