Advertisement

Bulletin of Materials Science

, Volume 24, Issue 1, pp 57–61 | Cite as

pH controlled dispersion and slip casting of Si3N4 in aqueous media

  • R. Ramachandra Rao
  • H. N. Roopa
  • T. S. Kannan
Article

Abstract

The dispersion characteristics of commercial Si3N4 powder in aqueous media (deionized water) was studied as a function of pH in the range 2–11. The slip was characterized for its dispersion quality by various experimental techniques like particle size analysis, sedimentation phenomena, viscosity and flow behaviour and zeta potential analysis. The optimum dispersion was found to be in the pH region 9–11 wherein the slurry displayed minimum sedimentation height, minimum viscosity, near Newtonian flow behaviour and maximum zeta potential. The slip is highly agglomerated in the pH range 2–8 as manifested by higher sedimentation height, higher viscosity, lower zeta potential and thixotropic non-Newtonian flow behaviour. The 72 wt% (44 vol.%) Si3N4 slips made at pH = 10 resulted in green bodies having 53–59% of theoretical density after casting into plaster molds.

Keywords

Dispersion slip casting Si3N4 slips 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Alford N McN, Birchall J D and Kendall K 1986Mater. Sci. & Technol. 2 329Google Scholar
  2. Bergstrom L and Pugh R J 1989J. Am. Ceram. Soc. 72 103CrossRefGoogle Scholar
  3. Bergstrom L and Bostedt E 1990Colloids & Surfaces 49 183CrossRefGoogle Scholar
  4. Brook R J 1985Mater. Sci & Eng. 71 305CrossRefGoogle Scholar
  5. Dutta S 1988Adv. Ceram. Mater. 3 257Google Scholar
  6. Freedman M R and Millard M L 1986Ceram. Eng. & Sci. Proc. 7 884Google Scholar
  7. Fries R and Rand B 1996Materials science and technology, A comprehensive treatment, inProcessing of ceramics, Part I (eds) R W Cahn, P Hassen and E J Kramer, (Vol. ed.) R J Brook (Germany: VCH publishers Inc.) Vol. 17A, Ch. 6Google Scholar
  8. Galassi C, Rastelli E, Roncari E, Ardizzone S and Cattania M G 1995J. Mater. Res. 10 339CrossRefGoogle Scholar
  9. Galassi C, Bertoni F, Ardizzone S and Bianchi C L 2000J. Mater. Res. 15 155Google Scholar
  10. Hirata Y 1997Ceram. Int. 23 93CrossRefGoogle Scholar
  11. Hirata Y, Nakagama S and Ishihara Y 1990J. Mater. Res. 5 640CrossRefGoogle Scholar
  12. Hoffmann M J, Nagel A, Greil P and Petzow G 1989J. Am. Ceram. Soc. 72 765CrossRefGoogle Scholar
  13. Kendall K 1992Ceramic technology international (ed.) I Birkby (London: Sterling Pub.) p. 47Google Scholar
  14. Lange F F 1983J. Am. Ceram. Soc. 66 396CrossRefGoogle Scholar
  15. Lange F F 1989J. Am. Ceram. Soc. 72 3CrossRefGoogle Scholar
  16. Li Y L, Liang Y, Zheng F, Xiao K, Hu Z Q and Shun T 1995J. Mater. Sci. Letts 14 713Google Scholar
  17. Moreno R, Salomoni A and Castanho S M 1998J. Eur. Ceram. Soc. 18 405CrossRefGoogle Scholar
  18. Nagel A and Petzow G 1989J. Eur. Ceram. Soc. 5 371CrossRefGoogle Scholar
  19. Persson M, Forsgren A, Carlstrom E, Kall L, Kronberg B, Pompe R and Carlsson R 1987High tech ceramics (ed.) P Vincenzini (Amsterdam: Elsevier Science) p. 623Google Scholar
  20. Peter Greil 1989Mater. Sci. & Eng. A109 27Google Scholar
  21. Ramachandra Rao R and Kannan T S 2000J. Am. Ceram. Soc. (accepted)Google Scholar
  22. Ramachandra Rao R, Roopa H N and Kannan T S 1999aCeram. Int. 25 223CrossRefGoogle Scholar
  23. Ramachandra Rao R, Roopa H N and Kannan T S 1999bJ. Eur. Ceram. Soc. 19 2145CrossRefGoogle Scholar
  24. Ramachandra Rao R, Roopa H N and Kannan T S 1999cJ. Eur. Ceram. Soc. 19 2763CrossRefGoogle Scholar
  25. Roosen A and Bowen H K 1988J. Am. Ceram. Soc. 17 970CrossRefGoogle Scholar
  26. Sato Y, Ueki M and Shintani K 1995J. Mater. Sci. 30 1373CrossRefGoogle Scholar
  27. Sheppard L M 1989Am. Ceram. Soc. Bull. 68 1815Google Scholar
  28. Somiya S 1984Advanced technical ceramics (Tokyo: Academic Press) Ch. 2Google Scholar
  29. Stadelmann H and Petzow G 1989J. Eur. Ceram. Soc. 5 155CrossRefGoogle Scholar
  30. Torre J P and Bigay Y 1986Ceram. Eng. Sci. Proc. 7 893CrossRefGoogle Scholar

Copyright information

© Indian Academy of Sciences 2001

Authors and Affiliations

  • R. Ramachandra Rao
    • 1
  • H. N. Roopa
    • 1
  • T. S. Kannan
    • 1
  1. 1.Materials Science DivisionNational Aerospace LaboratoriesBangaloreIndia

Personalised recommendations