Microstructure and properties of ZrB2-SiC composites prepared by spark plasma sintering using TaSi2 as sintering additive

ZrB2-SiC composites were fabricated by spark plasma sintering (SPS) using TaSi2 as sintering additive. The volume content of SiC was in a range of 10-30% and that of TaSi2 was 10-20% in the initial compositions. The composites could be densified at 1600 degrees C and the core-shell structure with the core being ZrB2 and the shell containing both Ta and Zr as (Zr,Ta)B-2 appeared in the samples. When the sintering temperature was increased up to 1800 degrees C only (Zr,Ta)B-2 and SiC phases could be detected in the samples and the core shell structure disappeared. Generally, the composites with core shell structure and fine-grained microstructure showed the higher electrical conductivity and Vickers hardness. The completely solid soluted composites with coarse-grained microstructure had the higher thermal conductivity and Young's modulus. (C) 2010 Elsevier Ltd. All rights reserved.