バイオフィルター用テーラーメイド細孔構造を有する窒化ケイ素多孔体の開発 : I. 焼結助剤の探索 [in Japanese] Development of Porous Silicon Nitride with Tailor-Made Pore Structure for Bio-Filter : I. Search of Sintering Aids [in Japanese]
Access this Article
Search this Article
In order to develop porous silicon nitride ceramics with tailor-made pore structure for "Bio-filter", suitable sintering aids were investigated. They must inhibit densification while promoting the α-β transformation to develop the fibrous β-Si<SUB>3</SUB>N<SUB>4</SUB> crystals that would be essential for high toughness. The conventional technique for developing porous Si<SUB>3</SUB>N<SUB>4</SUB> using a removable substance such as starch gave much lower porosity than the volume fraction of starch when MgO was used as a sintering aid. It was found that BaCO<SUB>3</SUB> met the necessary conditions, probably because the decomposition temperature was as high as the liquidus temperature, and the internal CO<SUB>2</SUB> pressure effectively inhibited the densification while promoting the phase transformation. The addition of 7 mol% as BaO gave about 44% of porosity at a sintering temperature as high as 1850°C. It was observed that the porous body consisted of interlocked fibrous β-Si<SUB>3</SUB>N<SUB>4</SUB> crystals with sub-micrometer pore sizes.
Shigen-to-Sozai 124(4), 245-248, 2008-05-25
The Mining and Materials Processing Institute of Japan