Kinetics and mechanisms of hydrothermal synthesis of barium titanate

Journal Article · Fri Nov 01 04:00:00 EST 1996 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1996.tb08728.x· OSTI ID:417779

Eckert, Jr, J O; Hung-Houston, C C; Gersten, B L; Lencka, M M; Riman, R E ^[1]

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1. Rutgers Univ., Piscataway, NJ (United States). Dept. of Ceramics

Reaction mechanisms for the hydrothermal synthesis of barium titanate are evaluated. Feedstocks of barium hydroxide octahydrate and anatase titania are reacted for varying durations (1--72 h) to provide intermediate-stage samples for characterization by transmission electron microscopy/energy-dispersive spectroscopy (TEM/EDS), X-ray diffractometry (XRD), and inductively coupled plasma spectroscopy (ICP) and XRD methods permits the analysis of data with the Johnson-Mehl-Avrami equation. This analysis reveals two reaction-rate regimes. Kinetic analysis, based on reaction progress, yields insight into the first reaction-rate regime but is inconclusive in the analysis of the second reaction-rate regime. In the first regime, at the early stage of barium titanate formation, a dissolution-precipitation mechanism dominates. In contrast, in the second regime, at longer reaction times, an in-situ transformation mechanism is probably dominant. However, multiple reaction mechanisms (e.g., in-situ transformation and dissolution-precipitation) may be competing for rate control. Alternatively, dissolution-precipitation may be the dominant mechanism throughout the barium titanate synthesis, with nucleation and growth controlling the first regime and dissolution rate controlling the second regime.

• Sponsoring Organization: National Science Foundation, Washington, DC (United States)
• OSTI ID: 417779
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 11 Vol. 79; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
BARIUM OXIDES
CHEMICAL REACTIONS
DISSOLUTION
ELECTRONIC EQUIPMENT
EXPERIMENTAL DATA
KINETICS
MATERIALS
PRECIPITATION
SYNTHESIS
TITANIUM OXIDES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY