Thermoelectric properties of alloys are improved through high temperature annealing in this technology. Materials with high thermoelectric properties are used in cooling and power generation applications.
The performance of thermoelectric devices is limited to the thermoelectric figure-of-merit (Z). Therefore to improve the performance of thermoelectric devices, Z has to be improved. This technology improves Z in alloys (metals or non-metals) by annealing them one or more times.
Alloys that have desirable thermoelectric properties are submitted to high temperatures between the solidus- where the alloy is completely solid- and the liquidus- where the alloy is completely liquid and then cooled again. Submitting a multicrystalline alloy to this process at least once allows portions of the alloy to melt and form new compositions (second phases), which create more grain boundaries. The process can be repeated to create three or more phases. An increased number of grain boundaries increases the phonon scattering and allows the material to exhibit a Z close to a superlattice structure.
Improves thermoelectric properties