Performance of thermoelectric modules depends on the properties of thermoelectric materials.
To manufacture Peltier modules, SCTB NORD applies only high-strength thermoelectric materials produced by the own thermoelectric material production department and using the powder metallurgical technique.
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
Density
kg/m3
3800
3300
Electric resistance
Ohm·cm
›1014
›1014
Young's modulus
GPa
372
331
Hardness (Knoop)
GPa
14.1
11.8
Ceramic color
white
grey
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.
