TY - JOUR
T1 - Nucleation and Formation Mechanisms of Hydrothermally Derived Barium Titanate
AU - Kerchner, Jeffrey A.
AU - Moon, J.
AU - Chodelka, R. E.
AU - Morrone, A. A.
AU - Adair, James H.
PY - 1998
Y1 - 1998
N2 - Barium titanate powders were produced using either an amorphous hydrous Ti gel or anatase precursor in a barium hydroxide (Ba(OH)2) solution via a hydrothermal technique in order to discern the nucleation and formation mechanisms of BaTiO3 as a function of Ti precursor characteristics. Isothermal reaction of the amorphous Ti hydrous gel and Ba(OH)2 suspension is believed to be limited by a phase boundary chemical interaction. In contrast, the proposed BaTiO3 formation mechanism from the anatase and Ba(OH)2 mixture entails a dissolution and recrystallization process. BaTiO3 crystallite nucleation, studied using high resolution transmission electron microscopy, was observed at relatively low temperatures (38°C) in the amorphous hydrous Ti gel and Ba(OH)2 mixture. Additional solution conditions required to form phase pure crystallites include a CO2-free environment, temperature >70°C and solution pH ≥13.4. Analysis of reaction kinetics at 75°C was performed using Hancock and Sharp's modification of the Johnson-Mehl-Avrami approach to compare observed microstructural evolution by transmission electron microscopy (I).
AB - Barium titanate powders were produced using either an amorphous hydrous Ti gel or anatase precursor in a barium hydroxide (Ba(OH)2) solution via a hydrothermal technique in order to discern the nucleation and formation mechanisms of BaTiO3 as a function of Ti precursor characteristics. Isothermal reaction of the amorphous Ti hydrous gel and Ba(OH)2 suspension is believed to be limited by a phase boundary chemical interaction. In contrast, the proposed BaTiO3 formation mechanism from the anatase and Ba(OH)2 mixture entails a dissolution and recrystallization process. BaTiO3 crystallite nucleation, studied using high resolution transmission electron microscopy, was observed at relatively low temperatures (38°C) in the amorphous hydrous Ti gel and Ba(OH)2 mixture. Additional solution conditions required to form phase pure crystallites include a CO2-free environment, temperature >70°C and solution pH ≥13.4. Analysis of reaction kinetics at 75°C was performed using Hancock and Sharp's modification of the Johnson-Mehl-Avrami approach to compare observed microstructural evolution by transmission electron microscopy (I).
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M3 - Article
AN - SCOPUS:0347759011
SN - 0097-6156
VL - 681
SP - 106
EP - 119
JO - ACS Symposium Series
JF - ACS Symposium Series
ER -