Effect of supercritical drying method on microstructure and properties of Al2O3 composites reinforced with ultrafine SiC particulate

Atsushi Nakahira, Toshihiro Murao, Shin Ichi Takeda, Masahiko Tajika, Toru Sekino, Yong Ho Choa, Koichi Niihara

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2 Citations (Scopus)


Mixtures of 95 vol% ultrafine γ-Al2O3 powder and 5 vol% ultrafine SiC powder, with average particle size of 40 nm, were mixed wet-ball milling and prepared by drying their slurry with a supercritical drying method and a microwave drying method. Al2O3 specimens dispersed with ultrafine-SiC particles as the secondary phase were hot-pressed, their powders being prepared by both the above drying methods. Difference between the superitical drying and the microwave drying method on the microstructure of Al2O3/5 vol%SiC composites was investigated. Dense Al2O3/SiC composites were obtained at lower hot-pressing temperatures when the mixture was prepared by supercritical drying method. Influence of the drying method on the γ- to α-Al2O3 transition behavior was also examined. Al2O3/SiC powder dried by the supercritical drying method showed narrow particle size distribution and the formation of soft agglomerates. Al2O3/SiC composite sintered by hot-pressing the powder dried with the supercritical drying method indicated relatively higher strength, whereas the strength of Al2O3/SiC composite through microwave drying method was low and had the large scatter.

Original languageEnglish
Pages (from-to)460-464
Number of pages5
JournalJournal of the Ceramic Society of Japan
Issue number5
Publication statusPublished - 1999


  • Microstructure
  • Microwave drying
  • Supercritical drying
  • Ultrafine SiC

ASJC Scopus subject areas

  • Ceramics and Composites
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry


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