Effect of reducing atmosphere on AIN ceramics sintered by millimerter Wave-HIP combined sintering

Kyohei Yamashita, Yoshihisa Kogo, Takashi Teranishi, Hidetaka Hayashi, Akira Kishimoto

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


The effect of reducing atmosphere on yttria dispersed AIN ceramics sintered by millimeter wave-HIP combined sintering was investigated. The specimens were sintered by millimeter wave (MMW) heating under nitrogen reducing atmosphere containing 3 vol% hydrogen followed by post-HIP treatment at 1700°C for 0.5 h under nitrogen pressure of 190 MPa. The relative densities to the theoretical one saturated at the first MMW heating over 1700°C. Thermal conductivities of AIN ceramics sintered by MMW heating under heavily reduced atmosphere with nitrogen were higher than that through MMW heating under normally reduced atmosphere. The thermal conductivity increased with decreasing the yttria additive amount and with increasing the sintering temperature. The optimized yttria dispersion amount was 1 wt% in the MMW heating at 1800°C for 0.5 h. Relative density and thermal conductivity increased by post-HIP treatment. The optimized yttria dispersion amount shifted from 1 wt% to 3 wt% after post-HIP treatment.

Original languageEnglish
Pages (from-to)17-21
Number of pages5
JournalFuntai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
Issue number1
Publication statusPublished - Jan 1 2012


  • AIN
  • Millimeter-wave heating
  • Post-HIP
  • Reducing atmosphere

ASJC Scopus subject areas

  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Metals and Alloys
  • Materials Chemistry


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