Given below are basic characteristics of Р and N type of thermoelectric materials, depending on the temperature (within 200 - 350 K):
Properties of ceramic substrates for thermoelectric modules
Employed in the thermoelectric module manufacture as a heat-conducting construction material are ceramic substrates of aluminum oxide containing no less than 96% of Al2O3. The standard substrate thickness ranges from 0.5 to 0.8 mm depending on the module design and geometry.
Today aluminum nitride ceramics with higher thermal conductivity and a lower thermal expansion coefficient is gaining acceptance.
Properties of Al2O3 ceramic vs AlN ceramic
|Properties||Units||Al2O3 ceramic||AlN ceramic|
|Thermal conductivity||W/(m·K)||32 - 36||160 - 180|
|Heat capacity at constant pressure||J/(kg·K)||775||730|
|Thermal expansion coefficient||10-6 /K||7 - 8||4.6|
The above properties are given for 25 °С.
Ceramic substrates of aluminum nitride are most commonly used for the manufacture of thermoelectric modules for telecommunication equipment.