|
Thermal conductivity is
the propensity for any material to transfer heat from one point to another. Of course for heat to "flow," it is
necessary for a difference of temperature to exist within a continuous section of the material. Thermal
conductivity is analogous to electrical conductivity. Similarly, thermal resistance is the inverse of thermal
conductivity as electrical resistance is the inverse of electrical conductivity. Coefficient of expansion
is the rate at which a material will grow in length with an increase in temperature. Most material grow in a
fairly linear fashion, particularly within a defined range of temperatures. A positive coefficient of expansion
indicates that the material gets longer as its temperature increases. Most metals are like that. Ice is a
well-known example of a negative coefficient of expansion, since it contracts in length with increasing
temperature (in other words, ice expands as it gets colder).
| Air (still) |
0.0003 |
|
|
|
| Alumina |
0.276 |
|
|
|
| Alumina (85%) |
0.118 |
|
|
|
| Aluminum |
2.165 |
0.23 |
2.7 |
0.81 |
| Beryllia (99.5%) |
1.969 |
|
|
|
| Beryllia (97%) |
1.575 |
|
|
|
| Beryllia (95%) |
1.161 |
|
|
|
| Beryllium |
1.772 |
|
|
|
| Beryllium-Copper |
1.063 |
|
|
|
| Boron Nitride |
0.394 |
|
|
|
| Brass (70/30) |
1.220 |
|
|
|
| Copper |
3.937 |
0.17 |
8.9 |
0.45 |
| Copper/Invc/Copper |
1.64 |
0.084 |
8.4 |
.020 |
| Copper/Mod/Copper |
1.82 |
0.060 |
9.9 |
0.18 |
| Copper/Mod-Cu/Copper |
2.45-2.80 |
0.60-0.10 |
9.4 |
0.26-0.30 |
| Diamond (room temp) |
6.299 |
|
|
|
| Epoxy |
0.002 |
|
|
|
| Epoxy (thermally conductive) |
0.008 |
|
|
|
| FR-4 (G-10) |
0.003 |
|
|
|
| GaAs |
0.591 |
|
|
|
| Glass |
0.008 |
|
|
|
| Gold |
2.913 |
|
|
|
| Heatsink Compound |
0.004 |
|
|
|
| Helium (liquid) |
0.000307 |
|
|
|
| Invar |
0.11 |
0.013 |
8.1 |
0.014 |
| Iron |
0.669 |
|
|
|
| Kovar |
0.17 |
0.59 |
8.3 |
0.020 |
| Lead |
0.343 |
|
|
|
| Magnesium |
1.575 |
|
|
|
| Mica |
0.007 |
|
|
|
| Molybdenum |
1.299 |
|
|
|
| Monel |
0.197 |
|
|
|
| Mylar |
0.002 |
|
|
|
| Nickel |
0.906 |
|
|
|
| Nitrogen (liquid) |
0.001411 |
|
|
|
| Phenolic |
0.002 |
|
|
|
| Platinum |
0.734 |
|
|
|
| Sapphire (a-axis) |
0.32 |
|
|
|
| Sapphire (c-axis) |
0.35 |
|
|
|
| Silicon (pure) |
1.457 |
|
|
|
| Silicon (0.0025 Ω-cm) |
1.457 |
|
|
|
| Silicon Carbide |
0.90 |
|
|
|
| Silicon Dioxide (amorphous) |
0.014 |
|
|
|
| Silicon Dioxide (quartz, a-axis) |
0.059 |
|
|
|
| Silicon Dioxide (quartz, c-axis) |
0.11 |
|
|
|
| Silicone Grease |
0.002 |
|
|
|
| Silicone Rubber |
0.002 |
|
|
|
| Silicon Nitride |
0.16 - 0.33 |
|
|
|
| Silver |
4.173 |
|
|
|
| Stainless Steel (321) |
0.146 |
|
|
|
| Stainless Steel (410) |
0.240 |
|
|
|
| Steel (low carbon) |
0.669 |
|
|
|
| Teflon |
0.002 |
|
|
|
| Tin |
0.630 |
|
|
|
| Titanium |
0.219 |
0.086 |
4.4 |
0.016 |
| Tungsten |
1.969 |
|
|
|
| Water |
0.0055 |
|
|
|
| Zinc |
1.024 |
|
|
|
| a: Approximate values from 0 °C to 100 °C b:
Thermal conductivity divided by specific gravity (introduced by Dr. Carl Zweben & K.A.
Schmidt) c: Invar d: Molybdenum
|
|
