Obtenção de elementos termoelétricos pelo processamento cerâmico de uma liga de Si-Ge

Abstract

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Semiconductors ceramics elements type-p have been prepared from silicon-gemanium alloy (Si80Ge20). Such elements are used in Radioisotopic Thermoelectric Generators (GTR) in energy conversion by thermoelectrical effects at high temperatures (~= 1000°C). The alloy was grown by the Czochralski technique under applied electric field, and by others fusion techniques for comparison. Samples with satisfactory homogeneity have been smashed and milled. The powder was then doped by mixing boron powder and pressed. The sintering was made by the PIES method (Pulverized and Intermixed Elements of Sintering), and by convencional ceramics processing. A sample prepared by Hot-Pressing Technique was used for comparison. The alloy grown by ECZ showed a good homogeneity. The density, grains regularity and chemical composition of the ceramics depend of the processing technique.