Thermal Contact Resistance and Thermal Conductivity of a Carbon Nanofiber

2005 ◽  
Author(s):  
Choongho Yu ◽  
Li Shi ◽  
Alan M. Cassell ◽  
Brett A. Cruden ◽  
Quoc Ngo ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Carbon Nanofiber ◽  
Thermal Contact ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
High Temperature Heat Treatment ◽  
Graphite Fibers ◽  
Platinum Layer

We have used a microfabricated device to measure the thermal contact resistance between a 152-nm-diameter carbon nanofiber and the measurement device, and found that heat conduction models based on Fourier’s law can underestimate the thermal contact resistance at the nanoscale constriction if a large reduction in the effective thermal conductivity of the constriction is not taken into account. With the thermal contact resistance reduced by the deposition of a platinum layer on the contact, we observed that the thermal conductivity of the carbon nanofiber grown by using a plasma enhanced chemical vapor deposition method is comparable to that of graphite fibers grown by pyrolysis of natural gas prior to high-temperature heat treatment.

Thermal Contact Resistance and Thermal Conductivity of a Carbon Nanofiber

2005 ◽  
Vol 128 (3) ◽  
pp. 234-239 ◽  
Author(s):  
Choongho Yu ◽  
Sanjoy Saha ◽  
Jianhua Zhou ◽  
Li Shi ◽  
Alan M. Cassell ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
Carbon Nanofiber ◽  
Thermal Contact ◽  
Mean Free Path ◽  
Total Thermal Resistance ◽  
Temperature Range ◽  
High Temperature Heat Treatment ◽  
Platinum Coating

We have measured the thermal resistance of a 152‐nm-diameter carbon nanofiber before and after a platinum layer was deposited on the contacts between the nanofiber and the measurement device. The contact resistance was reduced by the platinum coating for about 9–13% of the total thermal resistance of the nanofiber sample before the platinum coating. At a temperature of 300K, the axial thermal conductivity of the carbon nanofiber is about three times smaller than that of graphite fibers grown by pyrolysis of natural gas prior to high-temperature heat treatment, and increases with temperature in the temperature range between 150K and 310K. The phonon mean free path was found to be about 1.5nm and approximately temperature-independent. This feature and the absence of a peak in the thermal conductivity curve indicate that phonon-boundary and phonon-defect scattering dominate over phonon-phonon Umklapp scattering for the temperature range.

High‐Temperature Skin Softening Materials Overcoming the Trade‐Off between Thermal Conductivity and Thermal Contact Resistance

Small ◽  
2021 ◽  
pp. 2102128
Author(s):  
Taehun Kim ◽  
Seongkyun Kim ◽  
Eungchul Kim ◽  
Taesung Kim ◽  
Jungwan Cho ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Trade Off

Through-Plane Thermal Conductivity of PEMFC Porous Transport Layers

2010 ◽  
Vol 8 (2) ◽  
Author(s):  
Odne S. Burheim ◽  
Jon G. Pharoah ◽  
Hannah Lampert ◽  
Preben J. S. Vie ◽  
Signe Kjelstrup
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Residual Water ◽  
Order Of Magnitude ◽  
Thermal Conductivities

We report the through-plane thermal conductivities of the several widely used carbon porous transport layers (PTLs) and their thermal contact resistance to an aluminum polarization plate. We report these values both for wet and dry samples and at different compaction pressures. We show that depending on the type of PTL and the existence of residual water, the thermal conductivity of the materials varies from 0.15 W K−1 m−1 to 1.6 W K−1 m−1, one order of magnitude. This behavior is the same for the contact resistance varying from 0.8 m2 K W−1 to 11×10−4 m2 K W−1. For dry PTLs, the thermal conductivity decreases with increasing polytetrafluorethylene (PTFE) content and increases with residual water. These effects are explained by the behavior of air, water, and PTFE in between the PTL fibers. It is also found that Toray papers of differing thickness exhibit different thermal conductivities.

scholarly journals Effects of pressure and temperature on thermal contact resistance between different materials

2015 ◽  
Vol 19 (4) ◽  
pp. 1369-1372 ◽  
Author(s):  
Zhe Zhao ◽  
Hai-Ming Huang ◽  
Qing Wang ◽  
Song Ji
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Experimental Approach ◽  
Phenolic Resin ◽  
Thermal Conductivity Coefficient ◽  
Thermal Contact ◽  
Carbon Composites ◽  
Interfacial Temperature ◽  
Temperature And Pressure

To explore whether pressure and temperature can affect thermal contact resistance, we have proposed a new experimental approach for measurement of the thermal contact resistance. Taking the thermal contact resistance between phenolic resin and carbon-carbon composites, cuprum, and aluminum as the examples, the influence of the thermal contact resistance between specimens under pressure is tested by experiment. Two groups of experiments are performed and then an analysis on influencing factors of the thermal contact resistance is presented in this paper. The experimental results reveal that the thermal contact resistance depends not only on the thermal conductivity coefficient of materials, but on the interfacial temperature and pressure. Furthermore, the thermal contact resistance between cuprum and aluminum is more sensitive to pressure and temperature than that between phenolic resin and carbon-carbon composites.

Thermal Conductivity Measurements of Nylon 11-Carbon Nanofiber Nanocomposites

2005 ◽  
Author(s):  
Antonette T. Cummings ◽  
Li Shi ◽  
Joseph H. Koo
Keyword(s):  
Thermal Conductivity ◽  
Thermal Contact Resistance ◽  
Carbon Nanofiber ◽  
Thermal Contact ◽  
Conductivity Measurements ◽  
Fire Retardancy ◽  
Commercial Use ◽  
Transmission Electron ◽  
Nylon 11 ◽  
Microscopy Images

Nylon 11, a popular material for commercial use, has been combined with low-percent loads of carbon nanofibers (CNFs) to tailor mechanical, fire retardancy, and thermal properties. Transmission electron microscopy images show that the CNFs are randomly aligned in the polymer matrix. We show that the thermal conductivity is minimized at a certain percent loading of CNFs due to a large thermal contact resistance between the CNFs and the medium.

Effective Thermal Conductivity of Composites Reinforced with Curvilinearly Anisotropic Inclusions with Kapitza Contact Resistance

2006 ◽  
Vol 306-308 ◽  
pp. 775-780
Author(s):  
Tung Yang Chen
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Closed Form ◽  
Effective Thermal Conductivity ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Transversely Isotropic ◽  
Closed Form Expression ◽  
Form Expression ◽  
Micromechanical Models

Effective thermal conductivities of composites consisting of curvilinearly anisotropic inclusions with Kapitza thermal contact resistance between the constituents are considered. We show that the effect of these curvilinearly anisotropic inclusions can be exactly simulated by certain equivalent isotropic or transversely isotropic inclusions. Three different micromechanical models are employed to estimate the effective thermal conductivity of the composite. Interestingly, all these methods result in the same simple, closed-form expression.

Thermal Contact Resistance at a Metal Foam-Solid Surface Interface

2011 ◽  
Author(s):  
Ehsan Sadeghi ◽  
Scott Hsieh ◽  
Majid Bahrami
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Effective Thermal Conductivity ◽  
Contact Area ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Metal Foams ◽  
Real Contact Area ◽  
The Real ◽  
Real Contact

Accurate information on heat transfer and temperature distribution in metal foams is necessary for design and modeling of thermal-hydraulic systems incorporating metal foams. The analysis of this process requires determination of the effective thermal conductivity as well as the thermal contact resistance (TCR) associated with the interface between the metal foams and adjacent surfaces/layers. In the present study, a test bed that allows the separation of effective thermal conductivity and thermal contact resistance in metal foams is described. Measurements are performed in a vacuum under varying compressive loads using ERG Duocel aluminum foam samples with different porosities and pore densities. Also, a graphical method associated with a computer code is developed to demonstrate the distribution of contact spots and estimate the real contact area at the interface. Our results show that the porosity and the effective thermal conductivity remain unchanged with the variation of compression in the range of 0 to 2 MPa; but TCR decreases significantly with pressure due to an increase in the real contact area at the interface. Moreover, the ratio of real to nominal contact area varies between 0 to 0.013, depending upon the compressive force, porosity, and surface characteristics.

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