TY - JOUR
T1 - Alpha alumina transformation in seeded boehmite gels
AU - Shelleman, R. A.
AU - Messing, G. L.
AU - Kumagai, M.
N1 - Funding Information:
financial support of the Basic Energy Sciences Division of DOE through contract DE-AC02-81ER10949 is gratefully acknowledged.
PY - 1986/6/1
Y1 - 1986/6/1
N2 - The kinetics and surface area changes during the γ to α-Al2O3 transformation sequence of an α-Al2O3 seeded boehmite sol-gel are compared to an unseeded boehmite sol gel. The seeded gels exhibited increased kinetics, however the activation energy for the γ to α-Al3O3 transformation was lowered only 17% indicating the α-Al2O3 transformation is growth controlled. Transmission electron microscopy showed that each α-Al2O3 seed acts as a multiple nucleation site for the θ to α-Al2O3 transformation. The higher surface area of the seeded boehmite results from the prevention of vermicular microstructure development. Thus, by seeding boehmite sol gels with α-Al2O3 the growth process during transformation to α-Al2O3 is controlled resulting in a fine, uniform microstructure which sinters at significantly lower temperatures.
AB - The kinetics and surface area changes during the γ to α-Al2O3 transformation sequence of an α-Al2O3 seeded boehmite sol-gel are compared to an unseeded boehmite sol gel. The seeded gels exhibited increased kinetics, however the activation energy for the γ to α-Al3O3 transformation was lowered only 17% indicating the α-Al2O3 transformation is growth controlled. Transmission electron microscopy showed that each α-Al2O3 seed acts as a multiple nucleation site for the θ to α-Al2O3 transformation. The higher surface area of the seeded boehmite results from the prevention of vermicular microstructure development. Thus, by seeding boehmite sol gels with α-Al2O3 the growth process during transformation to α-Al2O3 is controlled resulting in a fine, uniform microstructure which sinters at significantly lower temperatures.
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U2 - 10.1016/0022-3093(86)90142-0
DO - 10.1016/0022-3093(86)90142-0
M3 - Article
AN - SCOPUS:0022078140
SN - 0022-3093
VL - 82
SP - 277
EP - 285
JO - Journal of Non-Crystalline Solids
JF - Journal of Non-Crystalline Solids
IS - 1-3
ER -