Thermal conductivities 2.3.7



	You are here:		Chapter: 2 General physics Section: 2.3 Temperature and heat SubSection: 2.3.7 Thermal conductivities

« Previous Subsection

Next Section »

2.3.7 Thermal conductivities

Definition and units

The thermal conductivity, λ, of a substance may be defined as the quantity of heat transmitted, Q, due to unit temperature gradient, in unit time under steady conditions in a direction normal to a surface of unit area, when the heat transfer is dependent only on the temperature gradient.

λ = − Q		∂T
		∂n

In this section thermal conductivity values are assembled for metallic, semi-conducting and insulating elements, representative groups of alloys, refractories and miscellaneous constructional and insulating materials, some liquids and some gases. The values are expressed in the SI unit W m⁻¹ K⁻¹ throughout. Factors for converting to other units are as follows:

1 W m⁻¹ K⁻¹ = 0.01 J cm cm⁻² s⁻¹ K⁻¹

= 0.002 388 cal cm cm⁻² s⁻¹ K⁻¹

= 0.859 8 kcal m m⁻² h⁻¹ K⁻¹

= 0.001 926 Btu in ft⁻² s⁻¹ °F⁻¹

= 6.933 Btu in ft⁻² h⁻¹ °F⁻¹

= 0.577 8 Btu ft ft⁻² h⁻¹ °F⁻¹

= 0.000 160 5 Btu ft ft⁻²s⁻¹ °F⁻¹

More extensive collections of thermal conductivity data will be found in Touloukian et al. (1970a, b and c).

Thermal conductivities of metallic elements

The thermal conductivity values in the table below are for metallic elements in the purest polycrystalline condition for which reliable measurements have been reported. Entries in italics relate to the liquid phase.

The thermal conductivities of less pure samples of these elements will be lower than the values given below. Thermal conductivity invariably decreases with decreasing purity; such dependence being weak at ambient and higher temperatures but very strong at cryogenic temperatures.

λ/(W m⁻¹ K⁻¹)
Metal	Temperature/K
Metal	173.2	273.2	373.2	573.2	973.2

Aluminium	241	236	240	233	92
Antimony	33	25.5	22	19	27
Beryllium	367	218	168	129	93
Bismuth	11	8.2	7.2	13	17
Cadmium	100	97	95	89	45
Caesium	37	36	20	*20.6*	*17.7*
Cerium	8	11	13	16	—
Chromium	120	96.5	92	82	66
Cobalt	130	105	89	69	53
Copper	420	403	395	381	354
Dysprosium	9	10.5	—	—	—
Erbium	14	15	—	—	—
Gadolinium	12	10	—	—	—
Gallium^†	43	41	33	45	—
Gold	324	319	313	299	272
Hafnium	25	23	22	21	21
Holmium	14	16	17	—	—
Indium	92	84	76	42	—
Iridium	156	147	145	139	—
Iron	99	83.5	72	56	34
Lanthanum	12	13	14.5	—	—
Lead	37	36	34	32	21
Lithium	94	86	82	47	59
Lutetium	18	17	—	—	—
Magnesium	160	157	154	150	—
Manganese	7	8	—	—	—
Mercury	29.5	*7.8*	*9.4*	*11.7*	—
Molybdenum	145	139	135	127	113
Nickel	113	94	83	67	71
Niobium	53	53	55	58	64
Osmium	93	88	87	87	—
Palladium	72	72	73	79	93
Platinum	73	72	72	73	78
Plutonium	4	6	8	—	—
Potassium	105	104	53	45	32
Praseodymium	9.9	12	13.4	—	—
Rhenium	52	49	47	44	45
Rhodium	156	151	147	137	—
Rubidium	59	58	32	29	22
Ruthenium	123	117	115	108	98
Samarium	10	13	13	14	—
Scandium	15	16	—	—	—
Silver	432	428	422	407	377
Sodium	141	142	88	78	60
Tantalum	58	57	58	58.5	60
Technetium	—	51	50	50	—
Terbium	11	10.5	—	—	—
Thallium	51	47	44	—	—
Thorium	55	54	54	56	58
Thulium	16	17	—	—	—
Tin	76	68	63	32	40
Titanium	26	22	21	19	21
Tungsten	188	177	163	139	119
Uranium	24	27	29	33	43
Vanadium	32	31	31	33	38
Yttrium	16.5	17	—	—	—
Zinc	117	117	112	104	66
Zirconium	26	23	22	21	23

Thermal conductivities of single crystals of some non-cubic metals at normal temperature

λ/(W m⁻¹K⁻¹)
Metal	Thermal conductivity in direction of
Metal	c-axis	a-axis	b-axis

Bismuth	5.4	9.3
Cadmium	83.05	104
Dysprosium	11.65	10.25
Erbium	18.4	12.6
Gadolinium	10.7	10.3
Gallium	16.0	40.8	88.3
Holmium	22.1	13.6
Lutetium	23.3	13.8
Mercury (at 227.7 K)	33.0	25.9
Terbium	14.5	9.45
Thulium	24.2	14.1
Tin	51.8	74.0

Thermal conductivities of alloys

At low temperatures the thermal conductivity of a given metal tends to increase in proportion to the reciprocal of its residual resistivity ρ₀. Many metals, especially good electrical conductors, have thermal conductivities that follow the simple relation

λ = L₀σT

at very low temperatures and at temperatures higher than their Debye temperature; L₀ being the Lorentz coefficient 2.45 × 10⁻⁸ W s⁻¹ K⁻², σ the electrical conductivity in S m⁻¹ and T the absolute temperature. This behaviour enables the thermal conductivities of metallic samples to be estimated fairly reliably from simple electrical resistivity measurements.

As the thermal conductivities of alloys depend strongly on their mechanical and thermal history (heat treatment) as well as on their chemical composition, the values tabulated below should be regarded as typical for the compositions listed. For many groups of alloys the thermal conductivity of a particular sample, near room temperature and above, can be estimated within about 6% from its more easily measured electrical conductivity using the relation λ = LσT + C. The optimum values for L and C for different alloy types are as follows:

Main constituent metal	L/(10⁻⁸ W s ⁻¹ K⁻²)	C/(W m ⁻¹K⁻¹)

Aluminium . . . . . . . . . . . . . . . . . . . . . . . .	2.22	10.5
Copper . . . . . . . . . . . . . . . . . . . . . . . . .	2.39	7.5
Alpha-iron . . . . . . . . . . . . . . . . . . . . . . .	2.43	9.2
Gamma-iron . . . . . . . . . . . . . . . . . . . . . .	2.39	4.2
Magnesium . . . . . . . . . . . . . . . . . . . . . .	2.21	9.6
Nickel . . . . . . . . . . . . . . . . . . . . . . . . .	2.13	8.4
Nickel-chromium (nimonic type) . . . . . . . . . . . .	2.20	6.0
Titanium . . . . . . . . . . . . . . . . . . . . . . . .	2.30	2.9
Zirconium . . . . . . . . . . . . . . . . . . . . . . .	2.50	2.2

Thermal conductivities of alloys at ambient and elevated temperatures


Alloy
	Composition / weight percent												λ / (W m⁻¹ K⁻¹) at Temperature / K
	Al	C	Cr	Cu	Fe	Mg	Mn	Ni	Si	W	Zn	Other	273	373	573	773	973	1273
Aluminium alloys Aluminium	100	—	—	—	—	—	—	—	—	—	—	—	236	240	233	—	—	—
Alpax gamma	87	—	—	—	0.3	0.3	0.3	—	12	—	—	—	188	188	184	—	—	—
Lo-Ex	85	—	—	1	0.5	0.9	—	1	11.8	—	—	—	172	175	173	—	—	—
Y-alloy	92	—	—	3.8	0.4	1.3	—	1.8	0.4	—	—	—	180	188	194	—	—	—
RR 59	93	—	—	2.3	1.2	1.5	—	1.2	0.9	—	—	—	168	176	186	—	—	—
RR 57	89	—	—	2.2	0.3	2.5	0.5	—	0.3	—	5	—	161	171	178	—	—	—
Copper alloys Copper	—	—	—	100	—	—	—	—	—	—	—	—	403	395	381	—	354	—
Brass	—	—	—	70	—	—	—	—	—	—	30	—	106	128	146	—	—	—
Bronze	—	—	—	90	—	—	—	—	—	—	—	10 Sn	53	60	80	—	—	—
German Silver	—	—	—	62	—	—	—	15	—	—	22	—	23	29	45	—	—	—
Constantan	—	—	—	60	—	—	—	40	—	—	—	—	22	24	27	—	—	—
Manganin	—	—	—	84	—	—	12	4	—	—	—	—	21	26	—	—	—	—
Nickel alloys Nickel	—	—	—	—	—	—	—	100	—	—	—	—	94	83	67	—	71	—
Alumel	2	—	—	—	—	—	2	95	1	—	—	—	30	32	35	—	—	—
Monel	—	0.2	—	29.2	1.7	0.1	1.0	67.1	—	—	—	—	21	24	30	—	43	—
Chromel P	—	—	10	—	—	—	—	90	—	—	—	—	—	19	23	—	—	—
Nichrome	—	0.1	21	—	0.6	—	0.65	77.3	0.4	—	—	—	13	14	17	—	21	—
Inconel 600	—	0.1	16	0.3	8	—	0.5	74	0.4	—	—	—	14.6	15.8	19.1	22.1	25.7	—
Inconel X-750	0.8	0.04	15	0.05	6.8	—	0.7	73	0.3	—	—	2.5Ti, 0.8 Nb	11.3	13.0	16.5	20.1	23.6	27.9
Incoloy 800	0.4	0.05	21	0.5	—	—	1	33	0.7	—	—	0.4 Ti	11.3	12.8	16.4	19.4	22.8	31
Incoloy 802	—	0.3	21	0.5	—	—	1	33	0.4	—	—	—	11.3	13.1	16.2	19.2	22.1	26
Hastelloy R-235	2	0.16	15.5	—	10	—	1	62	1	—	—	5.5 Mo, 2.5 Co	—	11.7	14.8	17.6	20	25.5
Nimonic 75	0.3	0.1	20	0.5	5	—	1	bal	1.0	—	—	2 Co, 0.3 Mo, 0.2 Ti	13.9	17.5	21.0	24.3	—
Nimonic 80	1.5	0.07	20	0.2	1	—	1	bal	1.0	—	—	2 Co, 0.3 Mo, 2 Ti	—	12.1	15.5	18.4	23.5	—
Nimonic 90	1.5	0.07	20	0.2	1	—	1	bal	1.5	—	—	17 Co, 0.3 Mo, 2 Ti	—	13.0	16.5	20.0	23.7	—
Nimonic 105	4.5	0.14	14.5	0.2	1	—	1	bal	1.0	—	—	20 Co, 5 Mo, 2 Ti	—	11.6	14.7	17.4	21.2	27.6

Carbon steels
0.08 C, 0.3 Mn	—	0.08	0.045	—	bal	—	0.31	0.07	0.08	—	—	—	59	58	49	40	32	28
0.23 C, 0.6 Mn	—	0.23	—	0.13	,,	—	0.64	0.07	0.11	—	—	—	52	51	46	39	32	27
0.42 C, 0.6 Mn	—	0.42	—	0.12	,,	—	0.64	0.06	0.11	—	—	—	52	51	46	38	30	27
0.8 C, 0.2 Mn	—	0.84	—	0.02	,,	—	0.24	—	0.13	—	—	—	51	49	42	36	31	27
1.2 C, 0.35 Mn	—	1.22	0.11	0.08	,,	—	0.35	0.13	0.16	—	—	—	45	45	40	35	28	26
0.2 C, 1.5 Mn	—	0.23	0.06	0.10	,,	—	1.51	0.04	0.12	—	—	—	46	46	43	37	31	27

Low alloy steels
0.3 C, 1 Cr	—	0.32	1.09	0.07	bal	—	0.7	0.07	0.20	—	—	—	49	46	42	36	29	28
0.4 C, 1 Cr, 0.3 Ni	—	0.35	0.88	0.12	,,	—	0.6	0.26	0.21	—	—	—	43	43	41	36	31	28
0.2 C, 0.6 Ni, 0.5 Mo	—	0.20	—	—	,,	—	1.35	0.6	0.25	—	—	0.5 Mo	37	38	37	34	29	—
0.3 C, 0.2 Cr, 3.5 Ni	—	0.33	0.17	0.08	,,	—	0.55	3.47	0.18	—	—	—	36	38	38	34	28	28
0.3 C, 1 Cr, 3.4 Ni	—	0.33	0.80	0.05	,,	—	0.53	3.38	0.17	—	—	—	34	36	37	35	29	28
0.4 C, 1 Cr, 3.6 Ni	—	0.4	0.8	—	,,	—	0.66	3.6	0.2	—	—	—	33	36	37.5	35	28	—
0.3 C, ! Cr, 3.5 Ni	—	0.34	0.78	0.05	,,	—	0.55	3.53	0.27	—	—	—	33	34	36	34	28	28
0.5 C, 1 Mn, 2 Si	—	0.49	0.04	0.09	,,	—	0.9	0.16	2.0	—	—	—	25	28	31	31	28	26

High alloy steels
1.2 C, 13 Mn	—	1.22	—	0.03	bal	—	13.0	0.07	0.22	—	—	—	13	15	18	21	23	26
0.3 C, 28 Ni	—	0.28	—	0.03	,,	—	0.9	28.4	0.15	—	—	—	13	15	18	21	23	28
4 Cr, 18 W, 1 V	—	0.72	4.26	0.06	,,	—	0.25	0.07	0.30	18.5	—	1 V	24	26	28	28	27	28
Kovar	—	0.02	—	—	54	—	0.47	29	—	—	—	17 Co	14.1	14.7	15.6	17.5	19.3	—

Stainless steels
304, 321, 347	—	0.05	17.5	—	bal	—	<2	9	<1	—	—	—	14.5	16.5	20	22.5	25.5	29.5
316	—	0.05	17	—	,,	—	<2	12	<1	—	—	2.5 Mo	13.5	15	18.5	21.5	24	28.5
310	—	0.1	24	—	,,	—	<2	20	<1	—	—	—	12	13.5	17.5	20.5	23	—
16 Cr, 20 Ni	—	0.01	16	—	,,	—	1.2	20	0.3	—	—	—	13.6	15.7	18.9	21.5	23.8	26.8
Era-ATV	—	0.5	15	—	,,	—	1.2	27	1.3	2.8	—	—	11	12.5	15.5	—	21.5	—
403, 405, 409	—	0.1	12	—	,,	—	<2	—	<1	—	—	—	—	25	26	27	—	—
430, 434	—	0.05	17	—	,,	—	<2	—	<1	—	—	1 Mo	—	22.2	22.9	23.7	24.4	—
410, 420	—	0.3	13	0.1	,,	—	0.5	0.5	0.4	—	—	—	—	—	23.6	24.6	26.3	28

Miscellaneous alloys
Platinum 90%, iridium 10% . . . . . . . . . . . . . . . . . . . .													31	—	—	—	—	—
Platinum 90%, rhodium 10% . . . . . . . . . . . . . . . . . . . .													38	—	—	—	—	—
Platinum 60%, rhodium 40% . . . . . . . . . . . . . . . . . . . .													46	51	58	69	—	—
Titanium 92.5%, aluminium 5%, tin 2.5% . . . . . . . . . . . . . . . .													7	8.3	10.5	—	—	—
Titanium 96%, aluminium 2%, manganese 2% . . . . . . . . . . . . . . .													9.3	10.5	10.7	—	—	—
Zirconium 93.1%, tin 6.7%, carbon 0.1% . . . . . . . . . . . . . . . .													—	8.7	12	—	—	—
Zirconium 97.5%, tin 2.3%, carbon 0.1% . . . . . . . . . . . . . . . .													—	11.3	13	—	—	—

Thermal conductivities of alloys used in low temperature applications

Alloy	λ/(W m⁻¹ K⁻¹)
	Composition/weight percent												Temperature/K
	Al	C	Cr	Cu	Fe	Mg	Mn	Ni	Si	Sn	Zn	Other	273.2	173	100	50	20	4

Aluminium alloys^†
Aluminium	99.99	—	—	—	—	—	—	—	—	—	—	—	228	—	295	870	4100	1075
(1 C) 1100-0	bal	—	—	1	—	0.05	0.05	—	1.0	—	0.05	—	205	—	228	315	225	45
(N3) 3003 F	,,	—	—	0.12	—	—	1.2	—	—	—	—	—	170	158	143	117	58	11
2219 T81	,,	—	—	6.3	—	0.02	0.3	—	0.20	—	0.1	—	118	—	68	46	26	—
(N8) 5083 0	,,	—	0.15	0.1	—	4.5	0.7	—	0.4	—	0.25	—	110	92	66	39	17	3.3
7039 T61	,,	—	0.2	0.1	—	2.8	0.25	—	0.2	—	4	—	150	—	96	64	30	14.7

Copper alloys
Copper	—	—	—	99.96	—	—	—	—	—	—	—	—	400	—	480	1230	3700	1450
ETP Cu	—	—	—	99.95	—	—	—	—	—	—	—	—	395	—	445	880	1320	325
OFHC Cu	—	—	—	99.95	—	—	—	—	—	—	—	—	400	—	460	750	900	200
Brass	—	—	—	70	—	—	—	—	—	—	30	—	106	92	70	45	21	4
Brass	—	—	—	65	—	—	—	—	—	—	35	—	113	—	59	—	—	—
Cupro-nickel	—	—	—	90	—	—	—	10	—	—	—	—	—	—	—	31	14	1
German Silver	—	—	—	62	—	—	—	15	—	—	22	—	23	20	—	—	—	—
Copper Beryllium	—	—	—	98	—	—	—	—	—	—	—	2 Be	—	—	—	24	10	2

Nickel alloys
Nickel	—	—	—	—	—	—	—	99.99	—	—	—	—	94	115	154	320	865	138
Inconel X	0.9	0.04	15	—	7	—	0.7	73	0.3	—	—	2.5 Ti	11.4	10	8.7	—	—	—
K. Monel	3	0.15	—	30	1	—	0.6	65	0.15	—	—	—	17	14	12	—	—	—
Hastelloy X	—	0.15	22	—	24	—	—	45	—	—	—	9 Mo	9.9	8	6.5	5	3	0.5
Inconel 718	0.4	0.04	18.6	—	18.5	—	—	—	—	—	—	1 Ti, 5 Nb, 3 Mo	10	8.7	7	4.8	2.6	0.4

Steels
Armco iron	—	0.02	—	—	99.8	—	0.03	—	—	—	—	—	76	83.6	95	109	65	13
2.5% Ni	—	0.1	—	—	bal	—	0.8	2.5	0.2	—	—	—	38	33	—	—	—	—
3.5% Ni	—	0.1	—	—	,,	—	0.8	3.5	0.2	—	—	—	34	29	21	—	—	—
5% Ni	—	0.1	—	—	,,	—	0.8	5	0.2	—	—	—	31	26	19	10.5	—	—
9% Ni	—	0.1	—	—	,,	—	0.8	9	0.2	—	—	—	28	23	16	8.5	3.5	1
Invar 36% Ni	—	0.07	—	—	,,	—	0.4	36	0.2	—	—	—	13.5	11	7.7	4.3	1.6	—

Stainless steels
304/306/321/347	—	0.05	18	—	bal	—	2	8–12	1	—	—	—	14.5	11.5	9	5.5	2	0.3
310	—	0.2	25	—	,,	—	2	20	1.5	—	—	—	11	8.3	6.9	4.3	1.7	—
16 Cr, 20 Ni	—	0.01	16.2	—	,,	—	1.2	20.2	0.28	—	—	—	13.6	11.5	9.3	6.0	2.4	0.4
15 Cr, 26 Ni	—	0.05	15	—	,,	—	1.4	26	0.4	—	—	1.3 Mo, 0.3 V	11.2	—	7.6	5.0	2.2	1.0

Titanium alloys
Titanium	—	—	—	—	—	—	—	—	—	—	—	99.9 Ti	22	26	31	40	28	14
Ti 5 Al 2.5 Sn	5	0.1	—	—	0.4	—	0.2	—	—	2.5	—	—	7.8	6.1	4.8	3.6	2.0	—
Ti 6 Al₄ V	6	0.05	—	—	—	—	—	—	—	—	—	4 V	7.0	5.4	4.0	2.5	1.3	—
Ti 13 V 11 Cr 3 Al	3	0.08	11	—	0.3	—	—	—	—	—	—	13 V	7.4	5.0	3.4	1.9	0.9	—

Thermal conductivities of elements which are semi-conductors or insulators

	λ/(W m⁻¹ K⁻¹)
Substance	Temperature/K
Substance	173.2	273.2	373.2	573.2	973.2

Boron	72	32	19	11	10
Carbon:
amorphous	1.1	1.5	1.8	2.2	2.5
diamond	1700–4900	1000–2600	700–1700	—	—
graphite	70–220	80–230	75–195	50–130	35–70
Pyrolytic graphite:
parallel to planes	3870	2130	1510	936	549
normal to planes	10.8	6.4	4.4	2.8	1.6
Germanium	113	67	46.5	29	17.5
Iodine	—	0.5	0.4	*0.09*	—
Phosphorus:
black	20	13	—	—	—
white (or yellow)	—	0.25	*0.18*	*0.16*	—
Selenium:
amorphous	0.23	0.43	—	—	—
crystalline:
parallel to c-axis	6.8	4.8	4.8	—	—
normal to c-axis	2.0	1.4	1.4	—	—
Silicon	330	168	108	65	32
Sulphur:
amorphous	0.18	0.20	—	0.17	—
polycrystalline	0.39	0.29	0.15	*0.17*	—
Tellurium:
parallel to c-axis	5.1	3.6	2.9	2.4	*6.3*
normal to c-axis	2.9	2.1	1.7	1.5	*6.3*

Thermal conductivities of refractory materials: Dense, polycrystalline, single-phase compounds

		λ/(W m⁻¹ K⁻¹)
Material	Chem. formula	Temperature/K
Material	Chem. formula	298	373	773	1273	1773

Oxides:
Alumina	Al₂O₃^†	38	35	11	7	6
Aluminosilicate	Al₆Si₂O₁₃	—	6	4.5	4	—
Beryllia	BeO	300	220	70	18	14
Calcia	CaO	—	15	8.7	7.8	—
Magnesia	MgO^†	40	35	16	7	6.5
Spinel	MgAl₂O₄	16	15	9	6	—
Silica	SiO₂ (vitreous)^†	1.6	1.7	2.1	5.0	—
Thoria	ThO₂	14	12	6	2	2
Titania	TiO₂	—	9.2	4.5	3.3	—
Urania	U₂O	12	8	4.5	3.2	—
Zirconia	ZrO₂(stabilised)^†	1.8	1.8	2.0	2.2	2.4
Zircon	ZrSiO₄	8	5.8	4.8	4.2	—
Quartz	SiO₂ (single crystal)
	along c-axis	11	8.3	5	—	—
	normal to c-axis	6.5	5	3.6	—	—

Carbides:
Boran carbide	B₄C	30	25	21	71	15
Silicon carbide	SiC	110	90	65	45	40
Titanium carbide	TiC	30	32	36	40	45
Tungsten carbide	WC	40	—	—	45	50
Zirconium carbide	ZrC	—	—	31	35	—

Nitrides:
Aluminium nitride	AlN	36	33	23	—	—
Silicon nitride	Si₃N₄ (1% MgO)	30	28	21	14.5	13
Titanium nitride	TiN	—	25	27	—	—

Borides:
Titanium diboride	TiB₂	—	70	64	—	—
Zirconium diboride	ZrB₂	—	73	67	—	—
Silicon (AXM–5Q)	Si	150	110	45	26	—
Graphite (POCO)	C (1.77 Mg m⁻³)	108	107	76	—	—

Thermal conductivities of oxide and silicate ceramics: Commercial products.

Composition and density may vary, values should be taken as typical of type.

		λ/(W m⁻¹ K⁻¹)
Material type	IEC classification	Temperature/K
Material type	IEC classification	298	373	773	1273	1773

Porcelains and clay-based
materials:
Siliceous	C-110, C-111	1.7–2.1	1.7–2.0	1.8–2.0	1.9–2.0	—
Steatite (normal)	C-220	5.5–6.0	—	2.8–3.7	—	—
Cordierite (dense)	C-410	1.5–2.5	1.5–2.5	—	—	—
Zircon (dense)	—	7	6	4	3.5	—
Clay-based refractories	C-512	2–3	2–3	2–3	2–3	—
Mullite	C-610	2–6	2–6	—	—	—

Oxides:
Alumina (>99.5%)^†	C-799	33	29	12	9	7
Alumina 95%^†	C-795	23	13	9	6	5
Alumina 90%^†	C-786	17	12	7	5	4
Alumina 85%	C-780	15	12	7	4	—
Beryllia > 99.5%	C-810	300	220	70	18	14
Magnesia (30% porous)^†	C-820	10–14	5–8	—	—	—
Thoria (sintered)	—	8–10	6–8	3–5	2–3	—
Titania (sintered)	C-310	2.5–4	—	—	—	—
Urania (sintered)	—	8–10	6.8	4–5	2–3	2
Zirconia (stabilised)	C-830	1.7–2.0	1.7–2.0	1.7–2.0	1.7–2.2	1.8–3.3

^† Values at high temperatures are influenced by radiation transmission.

For further information on refractory materials consult Morrell (1985).
For further information on the thermal conductivities of solid materials generally at high temperatures see, for example, Powell (1954).

Thermal conductivities of miscellaneous solids

The values below are for normal temperature, except where stated (K) and should be regarded as average values for the type of material specified. Values for the commoner polymers will be found in section 3.11.1.

Substance	λ/(W m⁻¹ K⁻¹)

Asbestos cloth	0.125
,, insulating board	0.11
,, paper	0.104
,, wool	0.055
Beeswax	0.25
Bitumen	0.17
Brick (dry)	0.8–1.2
Cardboard	0.21
Charcoal	0.2
Coal (1400)	0.2
Concrete*
cellular	0.1–0.2
lightweight aggregate	0.2–0.6
dense	0.6–1.8
Cotton wool	0.03
Cork, baked slab	0.038–0.046
,, granular	0.04
Diatomaceous powder	0.07
Ebonite, solid	0.17
,, cellular	0.03
Felt	0.04
Fibreboard, insulating	0.055
,, hardboard	0.125
Glass, borosilicate crown	1.1
,, double extra dense flint	0.55
Glass, light flint	0.85
,, Pyrex	1.1
Glass, mineral, ceramic fibre:**
wool blanket	0.035–0.07
rigid board	0.030–0.036
Ice (268)	2.3
,, (173)	3.9
Kapok	~ 0.035
Mica	0.6–0.7
Paper	~ 0.06
Paraffin wax	0.25
Plasterboard (gypsum)	~ 0.16
Plasticine	0.65–0.8
Plastics, solid (see sec 3.11.1)
Plastics, cellular: (varies with
density)	0.031–0.037
phenolic foam board	0.031–0.038
polystyrene, expanded board	0.035–0.055
polystyrene, expanded beads
polyurethane, gas-filled board	0.017–0.020
(fresh)
polyurethane, gas-filled	0.027
board (aged)
polyvinyl chloride, rigid foam
board	0.035–0.041
urea formaldehyde foam	0.030–0.032
Plywood	0.125
Pyrophyllite, normal to
plane	~ 2.0
Rubber, cellular*	~ 0.045
,, natural	~ 0.15
,, silicone	0.25–0.4
Sand, silver	0.3–0.4
Silica aerogel powder*	0.024
Soil, clay	~ 1.1
Timber, ordinary	0.14–0.17
,, balsa	0.055
Vermiculite granules	~ 0.065
Wool	~ 0.05

Thermal conductivites of liquids

Values below are for the thermodynamic temperature (K) shown in brackets. Linear relationships mostly hold for range covered. Liquid metal values are given in the table Thermal conductivities of metallic elements.

Liquid

λ/(W m⁻¹ K⁻¹)

Liquid

λ/(W m⁻¹ K⁻¹)


Acetone . . . . .	0.198 (193), 0.146 (333)	Glycerine . . . . .	0.286 (273), 0.292 (333)
Aniline . . . . .	0.172 (293)	Medicinal paraffin	0.127 (273), 0.125 (423)
Argon . . . . .	0.1260 (84.2), 0.1216 (87.3)	Methane . . . . .	0.2153 (93.2), 0.1964 (108.2)
Benzene . . . . .	0.147 (293), 0.137 (323)	Methyl alcohol . .	0.223 (233), 0.186 (333)
n-Butyl alcohol	0.167 (213), 0.106 (353)	Nitrogen . . . . .	0.1511 (69.1), 0.1480 (71.4)
Carbon monoxide	0.1589 (72.0), 0.1421 (80.8)	Oil, cylinder . . . .	0.152 (293), 0.142 (473)
Carbon tetrachloride	0.115 (253), 0.102 (333)	,, transformer . .	0.136 (273), 0.127 (373)
Dichlorodifluoro-		n-Propyl alcohol	0.168 (233), 0.148 (353)
methane . . . .	0.09 (253), 0.073 (293)	Toluene . . . . .	0.159 (193), 0.119 (353)
Ethyl alcohol . . .	0.189 (233), 0.150 (353)	Water . . . . . .	0.561 (273), 0.673 (353)
Ethyl benzene . .	0.152 (193), 0.117 (353)		0.686 (378–433), 0.598 (542)
Ethyl glycol . . .	0.252 (273), 0.264 (373)	Xenon . . . . . .	0.07 (173), 0.05 (223)

Thermal conductivities of some liquids and their vapours (λ/(W m⁻¹ K⁻¹))

In the table below the thermal conductivities of liquids at their equilibrium saturation pressure are compared with the values for their dilute vapours at the same temperatures.

H₂

C₆H₆

H₂O

KNO₃


Temperature/K	4	20	90	298	373	683

Vapour	1.25 × 10⁻⁴	0.0145	0.0057	0.0070	0.0217	—
Liquid	0.0275	0.1178	0.1198	0.1463	0.6819	0.425

Thermal conductivities of gases

The thermal conductivity of a gas is independent of pressure at normal pressures. It increases at high pressures and decreases at low pressures, e.g. for air below about 1 mm Hg. Values are given for a pressure of 1 atm.

λ/(10⁻² W m⁻¹K⁻¹)
Gas	Temperature/K					Gas	Temperature/K
Gas	73.2	173.2	273.2	373.2	1273.2	Gas	173.2	273.2	373.2	1273.2

Argon	—	1.09	1.63	2.12	5.0	Air	1.58	2.41	3.17	7.6
Bromine	—	—	0.4	0.6	—	Ammonia	—	2.18	3.38	—
Chlorine	—	—	0.79	1.15	—	Carbon dioxide	—	1.45	2.23	7.9
Fluorine	—	1.56	2.54	3.47	—	Carbon monoxide	1.51	2.32	3.04	—
Helium	5.95	10.45	14.22	17.77	41.9	Ethane	—	1.80	—	—
Hydrogen	5.09	11.24	16.82	21.18	—	Ethylene	—	1.64	—	—
Krypton	—	0.57	0.87	1.15	2.9	R₁₂(CF₂Cl₂)	—	0.85	1.35	—
Neon	1.74	3.37	4.65	5.66	12.8	Hydrogen sulphide	—	1.2	—	—
Nitrogen	—	1.59	2.40	3.09	7.4	Methane	1.88	3.02	—	—
Oxygen	—	1.59	2.45	3.23	8.6	Nitric oxide	1.54	2.38	—	—
Radon	—	—	0.33	0.45	—	Nitrous oxide	—	1.51	—	—
Xenon	—	0.34	0.52	0.70	1.9	Sulphur dioxide	—	0.77	—	—
						Water vapour	—	1.53	2.35	—

References

J. G. Hust and A. F. Clark (1971) The Lorentz ratio as a tool for predicting the thermal conductivity of metals and alloys, Mat. Research and Standards, 11(8), 22–24.
R. Morrell (1985) Handbook of Properties of Technical and Engineering Ceramics, Part 1, HMSO, London.
R. W. Powell (1954) Thermal conductivities of solid materials at high temperatures, Research, 7, 492–501.
R. W. Powell (1965) Correlation of metallic thermal and electrical conductivities for both solid and liquid phases, Int. J. Heat and Mass Transfer, 8, 1033–1045.
Y. S. Touloukian, R. W. Powell, C. Y. Ho and P. G. Klemens (1970a) Thermophysical Properties of Matter Volume 1: Thermal Conductivity: Metallic Elements and Alloys, IFI/Plenum Data Corp., New York, Washington.
Y. S. Touloukian, R. W. Powell, C. Y. Ho and P. G. Klemens (1970b) Thermophysical Properties of Matter Volume 2: Thermal Conductivity: Nonmetallic Solids, IFI/Plenum Data Corp., New York, Washington.
Y. S. Touloukian, P. E. Liley and S. C. Saxena (1970c) Thermophysical Properties of Matter Volume 3: Thermal Conductivity: Nonmetallic Liquids and Gases, IFI/Plenum Data Corp., New York, Washington.

R.Morrell

« Previous Subsection

Next Section »




	Home \| About \| Table of Contents \| Advanced Search \| Copyright \| Feedback \| Privacy \| ^ Top of Page ^

	This site is hosted and maintained by the National Physical Laboratory © 2008.