EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The need to reduce global warming and the usage of fossil fuels as well as the increased worldwide energy demand, led the researchers to discover alternative energy resources. Thermoelectric technology has been studied for more than two centuries and is based on the energy conversion of waste heat into electricity. The good reliability and scalability combined with the fact that no moving parts exist in these devices has inspired the worldwide interest for power generation and cooling applications. The discovery of new compounds and their optimization is significant for the community. The Half Heusler compounds have been extensively studied due to their use in the range of medium and high temperatures as well as for their mechanical and thermal stability. The major problem in these materials is the high thermal conductivity that fluctuates in the order of 10W/m.K. These materials can be synthesized in several ways such as arc melting, induction melting and microwave heating. Additional treatments including annealing and milling can contribute significantly to reducing the thermal conductivity. Mechanical involves mix of reactive components at nanoscale and induce chemical reactions in powder mixtures at room temperature. In this presentation a mechanical alloying is presented as a advantageous synthesis method to fabricate low-cost hafnium-free n-type (Zr,Ti)NiSn Half Heusler alloys. Furthermore, the preliminary thermoelectric results and the high thermoelectric performance are discussed in details.