Graphite as a Standard Reference Material
The Cryogenics Division (Boulder, Colorado) in conjunction with the Office of Standard Reference Materials (Gaithersburg, MD) of the National Bureau of Standards has been investigating graphite as a potential, extended temperature range, Standard Reference Material (SRM). A large number of isotropic, fine-grained graphite rods in various diameters have been obtained for homogeneity and stability investigations. Electrical resistivity and density measurements have been performed on numerous rods at temperatures from 4 to 300 K. Thermal conductivity measurements have been performed on thirteen specimens at about 20°C. These measurements show that transport property variations both between and within these rods is relatively large (approximately 10%). However, a correlation between these variables is shown to exist which will allow the calculation of thermal conductivity from simple and inexpensive electrical resistivity and density measurements to within about ± 2%.
KeywordsThermal Conductivity Electrical Resistivity Standard Reference Material Thermal Conductivity Measurement Advisory Report
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- 1.E. Fitzer, Thermophysical Properties of Solid Materials, Advisory Report 12 (1967); Advisory Report 38 (1972); Report 606 (1972), AGARD, NATO, France.Google Scholar
- 2.M. L. Minges, Evaluation of Selected Refractories as High-Temperature Thermophysical Property Calibration Materials, AFML Technical Report TR-73–278 (1974);Google Scholar