Extruded TE material on the basis of Bi2Te3-Sb2Te3 solid solutions has been received wide approval after revolutionary discovery of technology for production of ingots with big diameter (25-30 mm) made by SCTB Nord.
In 1997 year SCTB Nord started mass production of extruded P-type (report N122, Proceedings of XVI International Conference on Thermoelectrics, 1997, Drezden, Germany) and extruded N-type - in 2002 year (report N47 Proceedings of 2hd European Conference on Thermoelectrics, Poland, Krakow, 2004).
Thermoelectric material produced by extrusion possesses particularly high mechanical properties what help to produce modules with dice even 0.2 mm high.
In addition, the plastic deformation at high pressure ensures a high degree of texture and homogeneity. Thus, thermoelectric performance of extruded material is not only comparable to that of zone melted materials or materials obtained by Bridgeman method but even surpasses them. This allows to produce modules with thermoelectric figure- of merit 2.9x10-3 C at 25 degrees Celsius (in vacuum).
Technical parameters of extruded ingots is as follows:
- Length: 120 mm, 240 mm
- Diameter: 25 mm, 30 mm, 35 mm
- Electrical conductivity: 870-1430 Ohm-1cm-1
Thera are few specifications on produced extruded ingots applied for cooling and generating modules: Spec-RTM-30NP-6; GTM-30NP-3 (more).
Data on distribution of properties, ingot marking, package, ets, is represented in abovementioned Specs.
Some data not included in Specs is shown below:
Thermal and Mechanical Properties of Extruded Materials
|Compressive Strength (MPa)||54.0||66.0|
|Shear Strength (MPa)||16.0||21.0|
|Young's Module (GPa)||47.0||42.0|
Coefficient of Thermal Expansion (x10-6)
|Temperature||Along extrusion direction||Across extrusion direction|