Bulk alumina support with high tolerant strain and its reinforcing mechanisms

Abstract Bulk porous Al 2 O 3 support was fabricated using a mixture of fine α-Al 2 O 3 powder and Al(OH) 3 particles, followed by pressureless sintering at temperatures between 1100°C and 1300°C. Al 2 O 3 support with high surface area was obtained, due to the presence of transitional Al 2 O 3 phases that were produced by the decomposition of Al(OH) 3 even after sintering. The Al 2 O 3 support exhibited superior mechanical properties and high strain to failure, compared with those fabricated by traditional methods. The strain to failure increased with the amount of Al(OH) 3 in the mixture, but decreased with increasing sintering temperature. A conceptual model for the microstructural evolution and reinforcing mechanisms, based on transmission electron microscopy (TEM) observations, is proposed. It reveals that the interface bonding of the Al 2 O 3 boundaries formed at the initial nucleation stage during θ- to α-Al 2 O 3 transformation is stronger than that formed by subsequent grain growth. The interface bonding between the Al 2 O 3 grains, which came from the decomposition of Al(OH) 3 , is stronger than that between the original Al 2 O 3 grains in the starting mixture.