Sintering condition and microstructure of translucent silicon nitride ceramics

Junichi Hojo, Wenwu Yang, Miki Inada, Yumi Tanaka, Naoya Enomoto

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Translucent Si3N4 ceramics are expected to use for a special optical application in high temperature and corrosive environment owing to its high mechanical strength and thermal and chemical stability. To achieve the translucency of Si3N4 ceramics, fine-grained microstructure with an appropriate sintering aid is important to reduce light scattering. The Si3N4 ceramics were fabricated by spark-plasma sintering (SPS) with AlN-MgO additive. Fine α-Si3N4 powder with high purity was useful to obtain translucent Si3N4 sintered body. When the additive content was large, α-SiAlON formed, whereas β3-Si3N4 formed at a small additive content, revealing the high translucency of both phases in visible light region. The AlN/MgO ratio should be on the SiAlON forming line (AlN/MgO = 3/1) in Si3N4-AlN-MgO phase diagram. The short-time sintering at high temperature (1850 °C, 5 min) by SPS was effective to obtain the dense and fine-grained microstructure, and the transmittance of 22∼28% at the wavelength of 900 nm was achieved under the optimal conditions.

Original languageEnglish
Pages (from-to)575-581
Number of pages7
JournalFuntai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
Issue number12
Publication statusPublished - Dec 1 2014

All Science Journal Classification (ASJC) codes

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


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