溶出処理によるムライト質多孔体の製造

概要

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Porous mullite ceramics were prepared by leaching glassy matrixes with a mixed acid from the sintered samples with compositions Al_2O_3/SiO_2 = 1/3.3, 1/2, 1/1 and 3/2 in molar ratio. The shape of the mullite crystals were granular for the samples from submicron powder mixtures of Al_2O_3 and SiO_2 sintered at 1400°-1600℃. Addition of CaO, MgO, BaO, TiO_2, or Fe_2O_3 (5 wt%) to the Al_2O_3-SiO_2 system with composition Al_2O_3/SiO_2=1/3.3 promoted the formation of elongated or needle-like mullite crystals. Effects of these oxides on the formation of mullite grains with high aspect ratio were discussed on the basis of the ternary phase diagrams. Average pore sizes of the leached porous mullite ceramics were in the range of 0.4-3 μm, and became larger in the order of CaO>MgO>Fe_2O_3>none>BaO)> TiO_2 in additives. The pore size measured by mercury-penetration method agreed with that observed by SEM.
社団法人日本セラミックス協会の論文
1989-06-01