Electrically functional structural ceramics as thermoelectrics

© Fraunhofer IKTS
Thermoelectric module made of TiOx.
© Fraunhofer IKTS
Extruded B<sub>4</sub>C semi-finished tube for use as thermocouple.

Ceramic thermoelectrics are suitable for the use in thermoelectric generators (TEG) due to their high thermal and chemical stability, low thermal expansion, high availability, and low manufacturing costs as compared to other thermoelectric materials. Over the past ten years, Fraunhofer IKTS has built up extensive experience in the field of ceramic-based thermoelectric generators: synthesis, coating, joining, characterization, manufacture and integration of thermoelectric modules, system design and simulation of operating conditions and performance.

 

Services offered

 

  • Development of ceramic thermoelectrics such as titanium suboxide, boron carbide, mixed oxides for the demand-oriented adjustment of electrical and thermal conductivity and Seebeck coefficients (thermoelectric force)
  • Cost-efficient technologies for the production of ceramic thermoelectrics and ceramic thermoelectric components
  • Concepts and implementation for generators, sensors and temperature control
  • System adapted oxidation protection concepts for thermoelectric components
  • Material-specific connection concepts for ceramic thermoelectrics

 

Technical equipment

 

  • Complete technology chain for thermoelectric materials and components
  • Combined van der Paw/Hall/Seebeck measuring stand for room temperature up to 600 °C
  • Electrical conductivity measurement up to 1400 °C
  • Thermal conductivity measurement up to 1500 °C
  • Testing of thermoelectric modules up to 600 °C under thermal conditions close to operating conditions

 

Examples / references

 

  • Modified boron carbides for thermoelectric applications
  • Defined titanium suboxides with high Seebeck coefficient and oxidation protection layer, can be used up to 600 °C under air
  • p- and n-doped SiC materials with high electrical conductivity