Sintering of nanophase {gamma}-Al{sub 2}O{sub 3} powder

Journal Article · Thu Aug 01 04:00:00 EDT 1996 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1996.tb08962.x· OSTI ID:382472

Wu, S J; De Jonghe, L C ^[1]; Rahaman, M N ^[2]

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1. Lawrence Berkeley Lab., CA (United States). Materials Sciences Div.
2. Univ. of Missouri, Rolla, MO (United States). Dept. of Ceramic Engineering

The sintering of ultrafine {gamma}-Al{sub 2}O{sub 3} powder (particle size {approx}10--20 nm) prepared by an inert gas condensation technique was investigated in air at a constant heating rate of 10 C/min. Qualitatively, the kinetics followed those of transition aluminas prepared by other methods. Measurable shrinkage commenced at {approx}1,000 C and showed a region of rapid sintering between {approx}1,125 and 1,175 C followed by a transition to a much reduced sintering rate at higher temperatures. Starting from an initial density of {approx}0.60 relative to the theoretical value, the powder compact reached a relative density of 0.82 after sintering to 1,350 C. Compared to compacts prepared from the as-received powder, dispersion of the powder in water prior to compaction produced a drastic change in the microstructural evolution and a significant reduction in the densification rate during sintering. The incorporation of a step involving the rapid heating of the loose powder to {approx}1,300 C prior to compaction (which resulted in the transformation to {alpha}-Al{sub 2}O{sub 3}) provided a method for significantly increasing the density during sintering.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 382472
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 8 Vol. 79; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AIR
ALUMINIUM OXIDES
ANNEALING
BULK DENSITY
KINETICS
MICROSTRUCTURE
PARTICLE SIZE
POWDERS
SHRINKAGE
SINTERING
TEMPERATURE DEPENDENCE
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION