Sintering of Nanophase Γ-Al₂O₃ Powder
Green, David J. and Halloran, John and Johnson, David W. and Klein, Lisa
The sintering of ultrafine γ-Al2O3 powder (particle size ∼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 ∼ 1000°C and showed a region of rapid sintering between ∼1125° and 1175°C followed by a transition to a much reduced sintering rate at higher temperatures. Starting from an initial density of ∼0.60 relative to the theoretical value, the powder compact reached a relative density of 0.82 after sintering to 1350°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 ∼1300°C prior to compaction (which resulted in the transformation to α-Al2O3) provided a method for significantly increasing the density during sintering.
S. J. Wu et al., "Sintering of Nanophase Γ-Al₂O₃ Powder," Journal of the American Ceramic Society, Wiley-Blackwell, Jan 1996.
The definitive version is available at http://dx.doi.org/10.1111/j.1151-2916.1996.tb08962.x
Materials Science and Engineering
Article - Journal
© 1996 Wiley-Blackwell, All rights reserved.