Related Resources: heat transfer
Thermal Diffusivity Table
Heat Transfer Engineering and Design
In heat transfer analysis, thermal diffusivity is the thermal conductivity divided by density and specific heat capacity at constant pressure. It measures the rate of transfer of heat of a material from the hot side to the cold side. It has the SI unit of m²/s. Thermal diffusivity is usually denoted α but a , κ ,K , and D are also used. The formula is:
α = k / ( ρ cp )
where
- k is thermal conductivity (W/(m·K))
- ρ is density (kg/m³)
- cp is specific heat capacity (J/(kg·K))
Thermal diffusivity of selected materials and substances
Material |
Thermal Diffusivity (m2/s ) |
Thermal Diffusivity (mm2/s ) |
Pyrolytic graphite , parallel to layers |
1.22 × 10−3 |
1220 |
Silver, pure (99.9%) |
1.6563 × 10-4 |
165.63 |
Gold |
1.27 × 10-4 |
127 |
Copper at 25 °C |
1.11 × 10-4 |
111 |
Aluminium |
9.7 × 10-5 |
97 |
Al-10Si-Mn-Mg (Silafont 36) at 20 °C |
74.2 × 10−6 |
74.2 |
Aluminium 6061-T6 Alloy |
6.4 × 10-5 |
64 |
Al-5Mg-2Si-Mn (Magsimal-59) at 20 °C |
44.0 × 10−6 |
44.0 |
Steel , AISI 1010 (0.1% carbon) |
1.88 x 10-5 |
18.8 |
Steel , 1% carbon |
1.172 × 10-5 |
11.72 |
Steel, stainless 304A at 27 °C |
4.2 × 10−6 |
4.2 |
Steel, stainless 310 at 25 °C |
3.352 × 10−6 |
3.352 |
Inconel 600 at 25 °C |
3.428 × 10−6 |
3.428 |
Molybdenum (99.95%) at 25 °C |
54.3 × 10-6 |
54.3 |
Iron |
2.3 × 10 -5 |
23 |
Silicon |
8.8 × 10 -5 |
88 |
Quartz |
1.4 × 10-6 |
1.4 |
Carbon/carbon composite at 25 °C |
2.165 × 10 -4 |
216.5 |
Aluminium oxide (polycrystalline) |
1.20 × 10 -5 |
12.0 |
Silicon Dioxide (Polycrystalline) |
8.3 × 10 -7 |
0.83 |
Si 3 N 4 with CNTs 26 °C |
9.142 × 10-6 |
9.142 |
Si 3 N 4 without CNTs 26 °C |
8.605 × 10-6 |
8.605 |
PC (Polycarbonate) at 25 °C |
0.144 × 10-6 |
0.144 |
PP (Polypropylene) at 25 °C |
0.096 × 10-6 |
0.096 |
Paraffin at 25 °C |
0.081 × 10-6 |
0.081 |
PVC (Polyvinyl Chloride) |
8 × 10 -8 |
0.08 |
PTFE (Polytetrafluorethylene) at 25 °C |
0.124 × 10-6 |
0.124 |
Water at 25 °C |
0.143 × 10-6 |
0.143 |
Alcohol |
7 × 10 -8 |
0.07 |
Water vapour (1 atm, 400 K) |
2.338 × 10 -5 |
23.38 |
Air (300 K) |
1.9 × 10 -5 |
19 |
Argon (300 K, 1 atm) |
2.2 × 10 -5 |
22 |
Helium (300 K, 1 atm) |
1.9 × 10 -4 |
190 |
Hydrogen (300 K, 1 atm) |
1.6 × 10 -4 |
160 |
Nitrogen (300 K, 1 atm) |
2.2 × 10 -5 |
22 |
Pyrolytic graphite, normal to layers |
3.6 × 10-6 |
3.6 |
Sandstone |
1.12–1.19 × 10-6 |
1.15 |
Tin |
4.0 × 10 -5 |
40 |
Brick, common |
5.2 × 10 -7 |
0.52 |
Brick, adobe |
2.7 × 10 -7 |
0.27 |
Glass, window |
3.4 × 10 -7 |
0.34 |
Rubber |
0.89 - 1.3 × 10 -7 |
0.089 - 0.13 |
Nylon |
9 × 10 -8 |
0.09 |
Wood (Yellow Pine) |
8.2 × 10 -8 |
0.082 |
Oil, engine (saturated liquid, 100 °C) |
7.38 × 10 -8 |
0.0738 |