Growth of Tabular α-Al2O3 Grains on Porous Alumina Substrate |
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Authors: | Bang-Ying Yu Wen-Cheng J Wei |
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Affiliation: | Department of Materials Science and Engineering, National Taiwan University, Taiwan 106, Republic of China |
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Abstract: | Gradient, porous alumina ceramics were prepared with the characteristics of microsized tabular α-Al2O3 grains grown on a surface with a fine interlocking feature. The samples were formed by spin-coating diphasic aluminosilicate sol on porous alumina substrates. The sol consisted of nano-sized pseudo-boehmite (AlOOH) and hydrolyzed tetraethyl orthosilicate Si(OC2H5)4]. After drying and sintering at 1150°–1450°C, the crystallographic and chemical properties of the porous structures were investigated by analytical electron microscopy. The results show that the formation of tabular α-Al2O3 grains is controlled by the dissolution of fine Al2O3 in the diphasic material at the interface. The nucleation and growth of tabular α-Al2O3 grains proceeds heterogeneously at the Al2O3/glass interface by ripening nano-sized Al2O3 particles. |
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