Deficiency of natural energy resources on Earth makes advanced energy management a challenge. Efforts are taken to harness cheap, inexhaustible, eco-friendly renewable sources of energy. Among these, thermoelectric (TE) conversion is a promising principle. Best materials for TE application are non-conventional heavily doped semiconductors. In particular, high temperature stable silicides (higher manganese silicides = HMS, CrSi2 and others) represent suitable candidates for demanded TE applications operable at high temperature. A main aim of TE materials development is to improve the figure of merit ZT, which essentially depends on the energy band structure and scattering of carriers and phonons in the material. It is planned to investigate qualitatively the transport behaviour of HMS compacted from nano-sized powders, to optimize its properties by chemical synthesis, and to reach a reduction of the thermal conductivity in nano-crystalline material. Starting from the synthesis of nano-powders by melting and ball milling, forming of a nano-structure with suitable scaling will be optimized by a rapid hot pressing technology. CrSi2 and other high temperature silicides will be optimized in a similar way for high electrical and thermal conductivity. They shall be applied as contacting materials and interlayers, ending up to advanced materials and technology procedures for high temperature thermogenerators. Materials will be characterized by XRD, SEAD (structure), TEM, SEM (morphology), EDAX (analysis). Having achieved the targeted nano-structure, the TE properties will be measured in dependence on temperature for optimising the application-relevant material parameters. The performance of thermogenerator devices based on the new solutions will be tested by unique measuring techniques of the host. The fellow will deepen his knowledge and experience on TE materials and thermogenerator technology for high temperature and is expected to develop superior contacting methods.
Field of science
- /natural sciences/chemical sciences/inorganic chemistry/inorganic compounds
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