ISSN:
1551-2916
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Al2O3-based porous ceramics with high surface areas were fabricated by adding Al(OH)3 to the starting powder, followed by pressureless sintering at temperatures 〉1100°C. Three types of starting powders were used in the present study: pure α-Al2O3, α-Al2O3+ Al(OH)3, and α-Al2O3+ ZrO2+ Al(OH)3. The addition of Al(OH)3 considerably increased the surface area of the porous Al2O3, and the addition of ZrO2 further increased the surface area; a surface area as high as 36.39 m2/g was obtained, and the high surface area was retained at higher temperature. The pore size distribution of the specimens with high surface area was bimodal, with one peak at ∼100 nm and the other, which contributed most of the surface area, at ∼10 nm. X-ray analysis showed that in the sample with the fine pores and high surface area, there was θ-Al2O3 phase produced by the decomposition of Al(OH)3, presumably because the phase transformation of θ-Al2O3 to α-Al2O3 was incomplete after low-temperature sintering. Moreover, the porous Al2O3 with high surface area retained superior mechanical properties, attributed to the good sinterability of the fine α-Al2O3 powder used in the present study. The sintered specimens could be large and designed to any shape, because pressureless sintering was used for fabrication. The present approach provides a new way of fabricating porous Al2O3 ceramics that could be widely used as catalyst supports in industry, especially for high-temperature catalysis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1151-2916.2001.tb00687.x
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