Conductivity. CTE.
Specific heat.
Thermal design.
Thermal properties reference. Conductivity, expansion (CTE), specific heat, melting point. Material selection for thermal applications.
Key principles.
W/m·K
Copper 401, aluminum 235, steel 50, plastic 0.2.
Per °C expansion
Steel 12, aluminum 23, plastic 80-200, Invar 1.2 µm/m·°C.
J/kg·K
Heat capacity. Aluminum 900, steel 460, plastic 1500.
°C
Aluminum 660. Steel 1500. Tungsten 3400. Plastic varies.
Heat absorption
Melting absorbs heat. Used in heat pipes, PCM.
Surface property
Black anodize 0.9. Polished aluminum 0.05. Affects radiation.
FAQ
Best thermal conductor?
Diamond 2200, then copper 401, then silver 429, then aluminum 235 W/m·K.
Lowest CTE materials?
Invar 36 ~1.2 × 10⁻⁶/°C. Then ceramics ~2-5. Plastics 80-200 highest.
Why CTE matters?
Different CTE in mating parts causes thermal stress, dimensional drift over temperature.
Specific heat applications?
Cooling capacity calculation. Higher specific heat = more heat absorption per °C.
Phase change materials?
Wax, salt hydrates absorb heat at melting. Used in cooling, thermal storage.
Emissivity importance?
Radiation cooling depends on emissivity. Black surfaces emit more. Important at elevated temperature.