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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

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−1 K−1)

Metal

Thermal conductivity in direction of

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 −1 K−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   

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

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

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:

 

 

 

 

 

 

Boron 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

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.

  He H2 A 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

73.2

173.2

273.2

373.2

1273.2

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

 

 

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