Effect of Na addition on electric properties of Ca2Si sintered compacts

Abstract

Ca2Si powders have been synthesized by the thermal treatment of Mg2Si with NaI or Na2CO3 under Ca vapors, then sintered into compacts by sparking plasma sintering (SPS) technique. As a comparison, the compact was also sintered using Ca2Si with NaI powders by the SPS technique. The effect of Na addition on the structural, transport and thermoelectric properties of the Ca2Si compacts has been examined. All the samples show a p-type behavior in the measured temperature range. The Ca2Si with Na2CO3 by vapor phase growth shows a higher carrier concentration of 1.28×10 18 cm-3 conductivity about 10 times higher than Ca 2Si, and a power factor about 5 times higher than Ca2Si from 350K to 570K. © 2011 Ceramic Society of Japan.