Preparation of Eco-Friendly Fe₂VAl-Based Thermoelectric Materials Using Cast Iron Scrap Chips as a Source Material

Abstract

This study investigates the upgraded recycling of cast-iron scrap chips in synthesising Heusler alloys Fe₂VAl for thermoelectric materials. It mainly examines the microstructure and the thermoelectric performance of the products. The thermoelectric performance showed positive results, as the maximum power factor, the PF value, of p-type 2C.I.–V–Al prepared using cast-iron scrap chips (the prefix ‘C.I.’ presumably stands for ‘cast-iron scrap chips’) was 1604 µWm⁻¹K⁻² at 200°C, the highest PF value. Meanwhile, the undoped 2C.I.–V–Al prepared using cast-iron scrap chips showed an approximate two-fold improvement in the power factor value, with 967 µWm⁻¹K⁻² at 200°C, a higher PF value than those previously reported. Unfortunately, in this study, the n-type 2C.I.–V–Al specimen made from cast-iron scrap chips could not be fabricated due to the effect of unavoidable impurities in the cast-iron scrap chips. The use of cast-iron scrap chips to produce undoped and p-type 2C.I.–V–Al alloys can contribute towards eco-friendly and cost-effective production processes.

Fig. 7 Temperature dependence of power factor, PF, of the annealed Fe₂VAl samples at 900°C for 2 days and 450°C for 6 hours.