溶出処理によるムライト質多孔体の製造(第2報) : カオリンからのムライト結晶成長に及ぼす遷移金属酸化物の添加効果

概要

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Porous mullite ceramics were prepared from New Zealand kaolin with transition metal oxide (Ti02, Fe_2O_3, CuO, CoO, or ZnO), fired at 1300°-1600℃, by leaching the glassy matrix with a 5N sodium hydroxide solution at 153℃ under 5 atm. Addition of the transition metal oxides was effective on the densification of the kaolin. Leaching rate evaluated by the depth of the leached layer of the sintered body decreased with an increase in firing temperature. However, formation of spinel phase in the ZnO- or CoO-containing sample suppressed the leaching rate. The growth of the needle mullite crystals became remarkable with au increase in the amount of the additives as well as sintering temperature, resulting in the enlargement of the average pore size in the range of 500 to 5100Å. Purity of the porous mullite ceramic was highest(99.6 wt%) for the sample of CuO, fired at 1500℃ for 1 h.
社団法人日本セラミックス協会の論文
1990-04-01