Microstructure and densification of ZrB2-SiC composites prepared by spark plasma sintering

Akin İ., Hotta M., Sahin F., YUCEL O., GOLLER G., Goto T.

JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, vol.29, no.11, pp.2379-2385, 2009 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 29 Issue: 11
  • Publication Date: 2009
  • Doi Number: 10.1016/j.jeurceramsoc.2009.01.011
  • Journal Name: JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.2379-2385
  • Keywords: ZrB2, SiC, Microstructure, Spark plasma sintering, Mechanical properties, DIBORIDE-BASED CERAMICS, MECHANICAL-PROPERTIES, SILICON-CARBIDE, TEMPERATURE, FABRICATION, TIME
  • Istanbul Technical University Affiliated: Yes

Abstract

ZrB2-SiC composites were prepared by spark plasma sintering (SPS) at temperatures of 1800-2100 degrees C for 180-300 s under a pressure of 20 MPa and at higher temperatures of above 2100 degrees C without a holding time under 10 MPa. Densification, microstructure and mechanical properties of ZrB2-SiC composites were investigated. Fully dense ZrB2-SiC composites containing 20-60 mass% SiC with a relative density of more than 99% were obtained at 2000 and 2100 degrees C for 180 s. Below 2120 degrees C, microstructures consisted of equiaxed ZrB2 grains with a size of 2-5 mu m and alpha-SiC grains with a size of 2-4 mu m. Morphological change from equiaxed to elongated alpha-SiC grains was observed at higher temperatures. Vickers hardness of ZrB2-SiC composites increased with increasing sintering temperature and SiC content up to 60 mass%, and ZrB2-SiC composite containing 60 mass% SiC sintered at 2100 degrees C for 180 s had the highest value of 26.8 GPa. The highest fracture toughness was observed for ZrB2-SiC composites containing 50 mass% SiC independent of sintering temperatures. (C) 2009 Elsevier Ltd. All rights reserved.