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Morphological Forms of α‐Alumina Particles Synthesized in 1,4‐Butanediol Solution
Author(s) -
Cho Seung Beom,
Venigalla Sridhar,
Adair James H.
Publication year - 1996
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.1151-2916.1996.tb07884.x
Subject(s) - boehmite , reagent , materials science , oxide , phase (matter) , chemical engineering , precipitation , scanning electron microscope , inorganic chemistry , aluminium , chemistry , metallurgy , organic chemistry , composite material , physics , meteorology , engineering
Phase‐pure, monodispersed, hexagonal plates of single‐crystal α‐alumina (∼ 2 μm wide and ∼0.5 μm thick) have been prepared via precipitation by treating an aluminum hydrous oxide precursor in 1,4‐butanediol at 300°C under autogenous vapor pressure. Present work shows that KOH is the only reagent that precipitates an aluminum hydrous oxide precursor suitable to synthesize α‐alumina in 1,4‐butanediol solution. In contrast, the use of NaOH or NH 4 OH as the precipitating reagent for the precursor material does not yield the alpha phase. The solution pH at which the precursor materials are precipitated is also a critical factor for the formation of α‐Al 2 O 3 . Phase‐pure α‐alumina powders were also only synthesized from the aluminum hydrous oxide precursors precipitated in the pH range from 10 to 10.5. The results of X‐ray diffraction and scanning electron microscopy indicate that longer reaction times promote the phase transformation from the intermediate boehmite phase to α‐alumina. The complete transformation from boehmite to α‐alumina requires reaction times of about 12 h.