RESUMO
Owing to the energy and environmental issues, energy recovery technologies attract an increasing interest. Thermoelectric power generation is a recycling technology, which directly converts heat energy into electric energy by reusing waste heat. In this study, n-type Bi2Te2.7Se0.3 thermoelectric materials doped with Cu were fabricated by hot pressing. The Bi-Te system has excellent thermoelectric properties in the middle- and low-temperature ranges; when a certain amount of Cu dopant is added, the thermoelectric properties are improved. The thermoelectric properties of the samples doped with Cu were compared with those of the intrinsic Bi-Te-based sample without Cu doping. In addition, the effects of the Cu concentration on the thermoelectric-material structures were investigated.
RESUMO
Higher manganese silicide is generally used in thermoelectric devices between 700 K and 900 K. MnSi1.73Al0.005 samples were fabricated by two continuous solid-state reactions followed by hot pressing because the electrical conductivity of all the samples is strongly dependent on Al doping, showing superior thermoelectric performance to the as-synthesized higher manganese silicide. The solid-state-reaction was performed at 1173 K for 6 hours. The effects of the sintering temperature were examined by sintering at three different temperatures: 1273 K, 1323 K and 1373 K. For the surface, microstructural, and electrical properties, scanning electron microscopy, X-ray diffraction, and a series of electric conductivity, Seebeck coefficient, and thermal conductivity analyses were conducted, respectively. As a result, the optimal process temperature for Al-doped higher manganese silicide using a hot-press technique was determined.