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Direct Evidence on the Elimination of Pore by the Applied Pressure in Hot Isostatic Pressing of Alumina

Published online by Cambridge University Press:  15 February 2011

Seiki Fukai ,
Nozomu Uchida ,
Zenji Kato  and
Keizo Uematsu
Seiki Fukai
Affiliation:
Department of Chemistry, Nagaoka University of Technology, Nagaoka, Niigata, Japan.
Nozomu Uchida
Affiliation:
Department of Chemistry, Nagaoka University of Technology, Nagaoka, Niigata, Japan.
Zenji Kato
Affiliation:
Department of Chemistry, Nagaoka University of Technology, Nagaoka, Niigata, Japan.
Keizo Uematsu
Affiliation:
Department of Chemistry, Nagaoka University of Technology, Nagaoka, Niigata, Japan.
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Abstract

Removal of natural pore during capsule hot isostatic pressing (HIP) and normal sintering were examined directly with the novel liquid immersion technique, which can reveal details of micro-structure and characterize flaw-forming defects of microns-size in lightly densified specimens. The results were supplemented by the pore size measurement with the mercury porosimetry, microstructural examination with SEM as well as microstructural examination of specimens after final densification. The behaviors in both pore size and shape changes were different in HIP and normal sintering. Removal of large pores of microns-size started from the beginning of densification in HIP. Whereas large pores grow with densification in normal sintering. Large pores changes their shape drastically in HIP, but hardly changes in normal sintering. The behavior of pore in the early stage of densification is closely related to the microstructure of densified specimen; without HIP, large defects of processing origin are present in near-fully dense specimen. These observations were discussed in terms of current sintering theory.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 251: Symposium S – Pressure Effects on Materials Processing and Design , 1991 , 21
Copyright
Copyright © Materials Research Society 1992

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References

REFERENCES

1. Evans, A. G. and Tappin, G., "Effect of microstructure on the stress to propagate inherent flaws", Proc. Br. Ceram. Soc., 20, 275–97(1972)Google Scholar
2. Hodge, E. S., "Elevated-temperature compaction of metals and ceramics by gas pressures", Powder Met., 7, 168–201(1964)CrossRefGoogle Scholar
3. Sato, T., Endo, T. and Shimada, M., "Postsintering hot isostatic pressing of ceria-doped tetragonal zirconia/alumina composite in an argon-oxygen gas atmosphere", J. Am. Ceram. Soc., 72, 761–64(1989)Google Scholar
4. McCoy, J. K., Muttart, L. E. and Wills, R. R., "Continuous monitoring of volumetric change in ceramic powder compacts during hot isostatic pressing", Bull. Am. Ceram. Soc., 64, 1240–44(1985)Google Scholar
5. Kingery, W. D. and Francois, B., The sintering of crystalline oxides, I. Interaction between grain boundaries and pores, pp.471–96 in Sintering and Related Phenomena, Ed. by Kuczynski, G. C., Hooton, N. A. and Gibbon, C. F., Gordon and Breach, New Your (176)Google Scholar
6. Kellett, B. J. and Lange, F. F., "Thermodynamics of Densification: I. Sintering of s'imple particle arrays, equilibrium configurations, pore stability, and shrinkage", J. Am. Ceram. Soc., 72, 725–34(1989)Google Scholar
7. Miyashita, M., Kim, J.-Y., Uchida, N. and Uematsu, K., “Effect of applied pressure on the removal of processing defect in alumina ceramics and the resultant improvement of mechanical property”, submitted to publication in this volume.Google Scholar
8. Uematsu, K., Itakura, K., Uchida, N., Saito, K., Miyamoto, A. and Miyashita, T., "Hot isostatic pressing of alumina and examination of the hot isostatic pressing map", J. Am. Ceram. Soc., 73, 74–78(1990)Google Scholar
9. Kim, J.-Y., Okamoto, S., Uchida, N. and Uematsu, K., "Hot isostatic pressing of Y-TZP powder", J. Mater. Sci., 25, 4634–38(1990)Google Scholar
10. Uematsu, K., Kim, J.-Y., Miyashita, M., Uchida, N. and Saito, K., "Direct observation of internal structure in spray-dried alumina granules", J. Am. Ceram. Soc., 73, 2555–57(1990)CrossRefGoogle Scholar
11. Kim, J.-Y., Inoue, M., Kato, Z., Uchida, N., Saito, K. and Uematsu, K., "Direct observation of internal structure in spray-dried yttria-doped zirconia granule", J. Mater. Sci., 26, 2215–18(1991)Google Scholar
12. Uematsu, K., Miyashita, M., Kim, J.-Y., Kato, Z. and Uchida, N., "Effect of forming pressure on the internal structure of alumina green bodies examined with immersion liquid technique", J. Am. Ceram. Soc., 74, 2170–74 (1991)Google Scholar
13. Zheng, J. and Reed, J. S., "Effect of particle packing characteristics on solid -state sintering", J. Am. Ceram. Soc., 72, 810–17(1989)Google Scholar
14. Uematsu, K., Miyashita, M., Kim, J.-Y. and Uchida, N., “Direct study on the behavior of flaw-forming defect in sintering”, J. Am. Ceram. Soc., submitted for publicationGoogle Scholar
15. Helle, A. S., Easterling, K. E. and Ashby, M. F., "Hot isostatic pressing diagrams: New development", Acta Metall., 33, 2163–74(1985)Google Scholar