In heat transfer, the thermal conductivity of a substance, k, is an intensive property that indicates its ability to conduct heat. For most materials, the amount of heat conducted varies (usually non-linearly) with temperature.
Thermal conductivity is often measured with laser flash analysis. Alternative measurements are also established.
Mixtures may have variable thermal conductivities due to composition. Note that for gases in usual conditions, heat transfer by advection (caused by convection or turbulence for instance) is the dominant mechanism compared to conduction.
This table shows thermal conductivity in SI units of watts per metre-kelvin (W·m−1·K−1). Some measurements use the imperial unit BTUs per foot per hour per degree Fahrenheit ( =
Sortable list This concerns materials at atmospheric pressure and around .
Material Thermal conductivity[W·m−1·K−1]Notes Acrylic glass (Plexiglas V045i) 0.170–0.200 Alcohols, oils Aluminium Aluminium nitride Cheng, Zhe; Koh, Yee Rui; Mamun, Abdullah; Shi, Jingjing; Bai, Tingyu; Huynh, Kenny; Yates, Luke; Liu, Zeyu; Li, Ruiyang; Lee, Eungkyu; Liao, Michael E.; Wang, Yekan; Yu, Hsuan Ming; Kushimoto, Maki; Luo, Tengfei; Goorsky, Mark S.; Hopkins, Patrick E.; Amano, Hiroshi; Khan, Asif; Graham, Samuel (2020). "Experimental observation of high intrinsic thermal conductivity of AlN". Physical Review Materials. 4 (4): 044602. arXiv:1911.01595. Bibcode:2020PhRvM...4d4602C. doi:10.1103/PhysRevMaterials.4.044602. S2CID 207780348. For high-quality single crystal. Aluminium oxide Material Properties Data: Alumina (Aluminium Oxide) . Makeitfrom.com. Retrieved on 2013-04-17. Beryllium oxide –330 Bismuth Boron arsenide Cubic boron nitride Leichtfried, G.; et al. (2002). "13.5 Properties of diamond and cubic boron nitride". In P. Beiss; et al. (eds.). Landolt-Börnstein – Group VIII Advanced Materials and Technologies: Powder Metallurgy Data. Refractory, Hard and Intermetallic Materials. Landolt-Börnstein - Group VIII Advanced Materials and Technologies. Vol. 2A2. Berlin: Springer. pp. 118–139. doi:10.1007/b83029. ISBN 978-3-540-42961-6. Copper For main article, see Copper in heat exchangers. Diamond Fiberglass or foam-glass Germanium Gold Kapton (tape) Manganese Lowest thermal conductivity of any pure metal.Apart from maybe Neptunium (6.3 W/(m⋅K)) and Plutonium (6.74 W/(m⋅K)). Marble 2.070–2.940 Expanded polystyrene 0.033–0.046 Polyurethane foam Silica aerogel Silicon nitride or 177 Ceramics material. Silver Highest thermal conductivity of any pure metal. Snow (dry) 0.050–0.250Tantalum nitrideMetallic theta-phase Teflon Water
Analytical list Thermal conductivities have been measured with longitudinal heat flow methods where the experimental arrangement is so designed to accommodate heat flow in only the axial direction, temperatures are constant, and radial heat loss is prevented or minimized. For the sake of simplicity the conductivities that are found by that method in all of its variations are noted as L conductivities, those that are found by radial measurements of the sort are noted as R conductivities, and those that are found from periodic or transient heat flow are distinguished as P conductivities. Numerous variations of all of the above and various other methods have been discussed by some G. K. White, M. J. Laubits, D. R. Flynn, B. O. Peirce and R. W. Wilson and various other theorists who are noted in an international Data Series from Purdue University, Volume I pages 14a–38a.
This concerns materials at various temperatures and pressures. Material Thermal conductivity [W·m−1·K−1] Temperature [K] Electrical conductivity @ 293 K[Ω−1·m−1]NotesAcrylic glass (Plexiglas V045i) 0.17-0.19-0.2 - Note: There are no negative conductivities and the symbols that could be read that way are hyphens to separate various estimates and measurements.Air and thin air and high tech vacuums, macrostructure 0.024HyperPhysics, most from Young, Hugh D., University Physics, 7th Ed., Addison Wesley, 1992. Table 15-5. (most data should be at 293 K (20 °C; 68 °F))-0.0250.0262 (1 bar)0.0457 (1 bar)Formula valuesd=1 centimeterStandard Atmospheric Pressure0.02090.02350.0260ListWeast, Robert C., Editor-in chief, Handbook of Chemistry and Physics, 48th Edition, 1967-1968, Cleveland: The Chemical Rubber Co., 19670.1 atmosphere0.02090.02350.02600.01 atmospheres0.02090.02350.02590.001 atmospheres0.02050.02300.02540.0001 atmospheres0.01780.01960.021210−5atmospheres0.007600.007830.0080010−6atmospheres0.001130.001120.0011110−7atmospheres0.0001190.0001170.000115ListLasance, Clemens J., "The Thermal Conductivity of Air at Reduced Pressures and Length Scales," Electronics Cooling, November 2002, http://www.electronics-cooling.com/2002/11/the-thermal-conductivity-of-air-at-reduced-pressures-and-length-scales/ Retrieved 05:20, 10 April 2016 (UTC). 273-293-298300600233.2266.5299.9233.2266.5299.9233.2266.5299.9233.2266.5299.9233.2266.5299.9233.2266.5299.9233.2266.5299.9233.2266.5299.9 hiAerosols2.95-loAerosols7.83×10−15 (78.03%N2,21%O2,+0.93%Ar,+0.04%CO2) (1 atm)The plate distance is one centimeter, the special conductivity values were calculated from the Lasance approximation formula in The Thermal conductivity of Air at Reduced Pressures and Length Scales and the primary values were taken from Weast at the normal pressure tables in the CRC handbook on page E2.Let K0 is the normal conductivity at one bar (105 N/m2) pressure, Ke is its conductivity at special pressure and/or length scale. Let d is a plate distance in meters, P is an air pressure in Pascals (N/m2), T is temperature Kelvin, C is this Lasance constant 7.6 ⋅ 10−5 m ⋅ K/N and PP is the product P ⋅ d/T. The Lasance approximation formula is Ke/K0 = 1/(1+C/PP).Some readers might find the notation confusing since the original mK might be interpreted as milliKelvins when it is really meter-Kelvins. He(Lasance?) puts a one (1) at the end of his equation so that it appears like this: Ke/K0 = 1/(1+C/PP)(1). Eventually you can find out from his graph that the (1) at the end is not part of his formula and instead he is citing his graph.Air and thin air and high tech vacuums, microstructure Formula Valuesd=1 millimeterStandard Atmospheric Pressure0.02090.02350.02600.1 atmosphere0.02090.02350.02590.01 atmospheres0.02050.02300.02540.001 atmospheres0.01780.01960.02120.0001 atmospheres0.007600.007830.0080010−5 atmospheres0.001130.001120.0011110−6 atmospheres0.0001190.0001170.00011510−7 atmospheres0.00001190.00001170.0000116List233.2266.5299.9233.2266.5299.9233.2266.5299.9233.2266.5299.9233.2266.5299.9233.2266.5299.9233.2266.5299.9233.2266.5299.9All values calculated from the Lasance formula: Lasance, Clemens J., "The Thermal Conductivity of Air at Reduced Pressures and Length Scales," Electronics Cooling, November 2002. Plate separation = one millimeter.Air, standard air 0.009220.013750.018100.022260.026140.029700.033050.036330.039510.04560.05130.05690.06250.06720.07170.07590.07970.08350.0870List, TPRC 3, pp 511–12 100150200250300350400450500600700800900100011001200130014001500 Air, typical air 30°N JanuarySea Level: 0.025351000 meters: 0.025092000 meters: 0.024833000 meters: 0.0242930°N JulySea Level: 0.026601000 meters: 0.025902000 meters: 0.025433000 meters: 0.0249760°N JanuarySea Level: 0.022861000 meters: 0.023022000 meters: 0.022763000 meters: 0.02250List USSAS pp 103, 107 &123Dubin, Maurice; Sissenwine, Norman and Tewels, Sidney, NASA, AFCRL & ESSA US Standard Atmosphere Supplements, US Government Printing Office 1996. 288.52285.25281.87275.14304.58295.59289.56283.75257.28259.31256.08252.85 TPRC standard air is very nearly equivalent to typical air worldwide.Air, wet air ≈Typical Air Air in motor windings at normal pressure, Lasance approximations 360 Kelvins10−2 meters: 0.0303910−3 meters: 0.0303810−4 meters: 0.0303110−5 meters: 0.02959List, TPRC Vol 3 page 512. 360 An investigator has reported some high values for the thermal conductivity of some metal air laminates both varnished and otherwise. See Taylor, T.S., Elec. World Vol 76 (24), 1159–62, 1920 in TPRC Data Series Vol 2, pp 1037–9.Alcohols or oils 0.1-0.110-0.21-0.212 293-298-300Aluminium, alloy Mannchen 1931:92% Aluminum, 8% MagnesiumCast L72.8100.0126.4139.8Annealed L76.6104.6120.1135.688%Aluminium, 12% Magnesium Cast56.177.4101.3118.4Mever-Rassler 1940:93.0% Aluminium, 7.0% Magnesium108.7List 872733734768727337347687273373476348.2 Mannchen, W., Z Metalik..23, 193–6, 1931 in TPRC Volume 1 pages 478, 479 and 1447.
Mever-Rassler. The Mever-Rassler alloy has a density of 2.63 g cm−1. Mever-Rassler, F., Metallwirtschaft. 19, 713–21, 1940 in Volume 1 pages 478, 479 and 1464.Aluminium, pure 204.3-205-220-237Thermal conductivities of the elements (data page)-250214.6249.3CRC Aluminum99.996+% Pure Aluminum78015502320308038104510515057306220661069007080715071307020684063505650400028502100160012501000670500400340300247237235236237240240237232226220213List 293-29836647812345678910111213141516182025303540455060708090100150200250273300350400500600700800900 - Electrical resistivities of the elements (data page)
Cryogenic: up to 1.858 ⋅ 1011 at 4.2 K.Amundsen, T. and Olsen T., Phil. Mag., 11 (111), 561-74, 1965 in TPRC Data Series Volume 1 page 5.
Formula Values3.85 ⋅ 107 at 273.15K; 3.45 ⋅ 107 at 300K; 2.50 ⋅ 107 at 400K. This material is superconductive (electrical) at temperatures below 1.183 Kelvins. Weast page E-78Aluminum, ultrapure TPRC Aluminum99.9999% Pure Aluminum4102820012100157001880021300229002380024000235002270020200176001170077303180[?]23801230754532414344302248237236237240237232226220213List 12345678910111315202530405060708090100150200273.2300400500600700800900 These are not measured values.
Very high thermal conductivity measurements up to 22,600 w m−1 K−1 were reported by Fenton, E.W., Rogers, J.S. and Woods, S.D. in reference 570 on page 1458, 41, 2026–33, 1963. The data is listed on pages 6 through 8 and graphed on page 1 where Fenton and company are on curves 63 and 64.
Next the government-recommended values are listed and graphed on page 9.