Coefficient of Thermal Expansion (CTE)
Definition: The coefficient of thermal expansion is defined as the fractional increase in the length per unit rise in temperature.
The coefficient of thermal expansion for a material is usually specified over a temperature range because it varies depending on the temperature. The following values are given for a temperature around 20 °C. CTE is usually given in units of um/m/°C or ppm/°C.
| Material | CTE (ppm/°C) | Material | CTE (ppm/°C) | |
|---|---|---|---|---|
| AlAs | 4.9 | InAs | 4.52 | |
| AlP | 4.5 | InP | 4.75 | |
| Alumina | 6-7 | InSb | 5.37 | |
| AsSb | 4 | Invar | 1.3 | |
| Copper | 16.7 | Kovar | 5.9 | |
| Cu/I/Cu | 8.4 | Molybdenum | 7.0-7.1 | |
| Cu/Mo/Cu | 6 | Polymers | 50-200 | |
| Cu/Mo-Cu/Cu | 6-10 | S-glass | 16 | |
| E-glass | 54 | Silicon | 2.6 | |
| Epoxy | 55 | Silicon Nitride (Si3N4) | 3.2 | |
| Fused Silica | 0.55 | Silicone resins | 30-300 | |
| Gallium Arsenide (GaAs) | 6.86 | Tin-Lead Solder | 27 | |
| GaP | 4.5 | Titanium | 9.5 | |
| GaSb | 7.75 | Tungsten | 5.7-8.3 | |
| Germanium (Ge) | 5.8 |
Sources:
www.owlnet.rice.edu/~msci301/ThermalExpansion.pdf
www.matweb.com