Abstract
High-density ceramic materials from nanosize ceramic powders were produced by high pressure under nearly hydrostatic environment up to 5.6 GPa, on a special configuration in a toroidal-type apparatus, at room temperature. Attempts to use a common solid pressure transmitting medium, as NaCl, resulted in cracked samples. Lead and indium, which have an extremely low shear strength, proved to be the suitable choices as a pressure-transmitting medium to compact these ceramic materials, in order to obtain high-density samples. Transparent amorphous SiO2-gel and translucent γ−Al2O3 samples, in bulk, with volumes about 40 mm3, hard and crack-free were obtained. Densities over 90% of full density for the γ−Al2O3 samples and over 80% for the compacted SiO2-gel samples were obtained. In addition, from the density-pressure curve, the yield strength (σ) for γ−Al2O3 was estimated, for the first time, as 2.6 GPa. Vickers microhardness values were in the range of 5.7 GPa for the γ−Al2O3 samples, and 4.0 GPa for the SiO2-gel samples, under loads of 50 g. An important and practical application of these results is the possibility of producing bulk γ−Al2O3, a new alumina material, which was not possible to prepare before due to the conversion to a phase during the normal sintering process. Additionally, specially for SiO2-gel, a very important application of this study is the possibility of incorporation of organic substances in an inorganic matrix, using high pressure at room temperature.
Similar content being viewed by others
References
J. Karch, R. Birringer, and H. Gleiter, Nature (London) 330, 556 (1987).
R. A. Andrievskii, O. M. Grebtsova, E. P. Domashneva, I. A. Kiyanskii, E. N. Kurkin, V. E. Perel’man, V. I. Sinitsyn, O. D. Torbova, and V. I. Torbov, Phys. Dokl. 38. 308 (1993).
V. Provenzano, N. P. Louat, M. A. Iman, and K. Sadanada, Nanostructured Mater. 1, 89 (1992).
J. A. Eastman, Y. X. Liao, A. Narayanasam, and R. W. Siegel, in Processing Science of Advanced Ceramics, edited by I. A. Aksay, G. L. McVay, and D. R. Ulrich (Mater. Res. Soc. Symp. Proc. 155, Pittsburgh, PA, 1989), p. 255.
R. W. Siegel, Nanostructured Mater. 3, 1 (1993).
A. O. Kunrath Neto, Study of Ceramic Sintering by High-Pressure (in Portuguese), Master Thesis-UFRGS/PPGEMM (1990).
A. Pechenik, G. J. Piermarini, and S. C. Danforth, Nanostructured Mater. 2, 479 (1993).
M. R. Gallas, B. Hockey, A. Pechenik, and G. J. Piermarini, J. Am. Ceram. Soc. 77, 2107 (1994).
D. L. Woods and E. M. Rabinovich, Appl. Spectrosc. 43, 263 (1989).
W. L. Vasconcelos, R. T. DeHoff, and L. L. Hench, J. Non-Cryst. Solids 121, 124 (1990).
C. J. Brinker and G. S. Scherer, Sol-Gel Science: The Physics and Chemistry of Sol-Gel Processing (Academic Press, New York, 1990).
S. Sakka, K. Aoki, H. Kozuka, and J. Yamaguchi, J. Mater. Sci. 28, 4607 (1993).
M. Wakatsuki, K. Ichinose, and T. Aoki, Jpn. J. Appl. Phys. 1, 578 (1972).
L. G. Khvostantsev, High Temp.–High Press. 16, 165 (1984).
W. F. Sherman and A. A. Stadtmuller, Experimental Techniques in High-Pressure Research (John Wiley & Sons Ltd., New York, 1987).
J. F. Baumard and P. Coupelle, J. Mater. Sci. Lett. 13, 93 (1994).
E. Arzt, Acta Metall. 30, 1883 (1982).
A. S. Helle, K. E. Easterling, and M. F. Ashby, Acta Metall. 33, 2163 (1985).
R. W. Heckel, Trans. Metall. Soc. AIME 221, 1001 (1961).
K. Lark-Horowitz and V. A. Johnson, in Methods of Experimental Physics, edited by M. Metzger (Academic Press, New York, 1959).
K. Yonagisawa, M. Nishioka, K. Yoku, and N. Yamasaki, J. Mater. Sci. Lett. 12, 1073 (1993).
J. Y. Ying, J. B. Benziger, and A. Navrotsky, J. Am. Ceram. Soc. 76, 2571 (1993).
M. R. Gallas, T. M. H. Costa, E. V. Benvenutti, A. R. Rosa, and J. A. H. da Jornada, High Pressure Drying and Compaction of Nanosize Silica Gel, First National Symposium of Glass, Águas de Lindóia, São Paulo, 1995.
T. M. H. Costa, M. R. Gallas, E. V. Benvenutti, and J. A. H. da Jornada, unpublished research.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gallas, M.R., Rosa, A.R., Costa, T.H. et al. High pressure compaction of nanosize ceramic powders. Journal of Materials Research 12, 764–768 (1997). https://doi.org/10.1557/JMR.1997.0111
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1557/JMR.1997.0111