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A Novel Technique for Synthesizing Nanoshell Hollow Alumina Particles
Author(s) -
Wang Yenwen,
Tseng Wenjea J.
Publication year - 2009
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2008.02653.x
Subject(s) - nanoshell , materials science , nanotechnology , chemical engineering , nanoparticle , engineering
A novel and versatile synthesis route has been developed to fabricate hollow Al 2 O 3 microspheres with nanoporous shell structures. The method involves a preferential “implantation” of Al species into polymeric template particles to form a core–shell structure in solvent. The template cores can then be removed by thermal pyrolysis to form hollow interiors. This unique “implantation” process allows for synthesis of monodisperse hollow spheres with a nonaggregated character. The implantation of Al species is confirmed by electron spectroscopy for chemical analysis/Auger analysis in depth profiles. The shell structure changes from amorphous to γ‐Al 2 O 3 at 900°C; because of which, the shell is nanoporous in structure. The porous shell then transforms to α‐Al 2 O 3 as temperature is further raised above 1000°C. Transmission electron microscopy examination reveals a uniform shell thickness of ca. 20–40 nm, and grain growth appears to be constrained by the thin shell walls at 1100°C, leading to void formation at the triple grain junctions.