Low temperature transport properties of pyrolytic graphite sheet. (September 2017)

• Record Type: Journal Article
• Authors: Nakamura, Sachiko; Miyafuji, Daisuke; Fujii, Takenori; Matsui, Tomohiro; Fukuyama, Hiroshi
• Is Part Of: Cryogenics. Volume 86(2017)
• Page Start: 118
• Page End: 122
• Publication Date: 2017-09
• Subjects: Graphite -- Thermal link -- Thermal conductivity -- Electrical conductivity -- X-ray diffraction -- Raman spectroscopy; Low temperature engineering -- Periodicals; Low temperature research -- Periodicals; 536.56
• DOI: 10.1016/j.cryogenics.2017.08.004
• Languages: English
• ISSNs: 0011-2275

Abstract

Highlights: We characterized transport properties of Pyrolytic Graphite Sheet (PGS). Thinner PGS has higher crystallinity and higher electrical/thermal conductivities. Electrical and thermal conductivities of graphite-family have some relationship. PGS is advantageous for applications as a thermal link at 60–300 K. Abstract: We have made thermal and electrical transport measurements of uncompressed pyrolytic graphite sheet (uPGS), a mass-produced thin graphite sheet with various thicknesses between 10 and 100 μ m, at temperatures between 2 and 300 K. Compared to exfoliated graphite sheets like Grafoil, uPGS has much higher conductivities by an order of magnitude because of its high crystallinity confirmed by X-ray diffraction and Raman spectroscopy. This material is advantageous as a thermal link of light weight in a wide temperature range particularly above 60 K where the thermal conductivity is much higher than common thermal conductors such as copper and aluminum alloys. We also found a general relationship between thermal and electrical conductivities in graphite-based materials which have highly anisotropic conductivities. This would be useful to estimate thermal conductance of a cryogenic part made of these materials from its electrical conductance more easily measurable at low temperature.