Reclaim of Wrecked Bi-Te Based Materials In Peltier Modules In Thermopower Properties By Mechanical Milling

Abstract

We thoroughly evaluated the effects of various treatments on the structural and electrical properties of the two as-cast materials, “Sb-doping Bi-Te (p-type)” and “Se-doping Bi-Te (n-type)” which are frequently present in abandoned Peltier modules. To investigate the thermoelectric properties of Bi2Te3-based materials, waste alloys characterized by electrical conductivity using the hot-end method. Alloys were purified by performing arc melting on a water-cooled copper crucible in a vacuum of at least 10-3 mbar, with five times melting sessions to assure homogeneity. A single and long milling period of 144 hours is applied. After the compressing operation, the resulting discs with nanostructures were annealed for an hour at 600 K under vacuum conditions. The discs' structural properties were characterized using X-ray diffraction (XRD) and their surfaces and stoichiometries were determined using scanning electron microscopy with an energy dispersive feature. The Seebeck coefficient of the nanoparticle formed n-type Bi-Te based sample is -35.3 µV.K-1 and p-type Bi-Te based sample is 100 µV.K-1 (15% of mean error margin). It was found that a notable improvement was attained in comparison to the initial state with the addition of nanoparticles.We thoroughly evaluated the effects of various treatments on the structural and electrical properties of the two as-cast materials, “Sb-doping Bi-Te (p-type)” and “Se-doping Bi-Te (n-type)”, which are frequently present in abandoned Peltier modules. To investigate the thermoelectric properties of Bi2Te3-based materials, waste alloys were produced and separated by electrical conductivity using the hot-end method. The alloys were purified by performing arc melting on a water-cooled copper crucible in a vacuum of at least 10-3 mbar, with 5 times melting sessions to assure homogeneity. A ball-milled procedure was used to reduce the obtained mass-scale materials to nano sizes. Single and long milling period of 144 hours is applied. After the compressing operation, the resulting discs with nano-structures were annealed for an hour at 600 K in a vacuum. X-ray diffraction was used to characterize the discs' structures, while scanning electron microscopy and energy dispersive X-ray spectroscopy were used to examine the discs' surfaces and determine their morphologies. Based on thermal imaging camera scans and Si-diode, we know that the Seebeck coefficient of the nanoparticle formed n-type Bi-Te based sample is -35.37 V.K-1, while that of the nanoparticle formed p-type Bi-Te based sample is 100.05 V.K-1 (15% of mean error margin). It was found that a notable improvement was attained in comparison to the initial state with the addition of nanoparticles.