In-situ synthesis of n-type unfilled skutterudite with reduced thermal conductivity by hybrid flash-spark plasma sintering

摘要

N-type skutterudite Ni0.15Co0.85Sb3 was obtained using a reactive sintering process using a derivative of the Spark Plasma Sintering (SPS) method (hybrid Flash-SPS). This used extremely high heating rates (9000 degrees C/min) to reach a temperature of 750 degrees C. This new technique produced in a short time (10 min) dense and nearly single-phase skutterudite. The material showed reduced thermal conductivity (2.5 W/m*K) and almost unchanged electrical properties when compared to a conventional SPSed sample; the ZT was 0.81 at 550 degrees C. It is also shown that the high heating rate, not the holding time, was the origin of these improvements. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.