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Journal of Materials Science

, Volume 49, Issue 14, pp 4780–4789 | Cite as

The influence of the nitriding parameters on the microstructure and strength of the open-cell reaction bonded silicon nitride foams fabricated via wet processing

  • Ali Alem
  • Robin A. L. Drew
  • Martin D. Pugh
Article

Abstract

In this study, the parameters which influence strength of the open-cell reaction bonded silicon nitride foams were investigated. These parameters include the monomer content in the suspension, the porosity level of the foam, the nitriding atmosphere including N2 and N2–4 %H2, and the nitriding temperature ranging from 1350 to 1425 °C. The nitriding mechanisms dominating under different nitriding conditions were also studied based on the phase and microstructural analysis. It was observed that there is a minimum monomer concentration of 25 wt% required in the premix solution to obtain a defect-free and homogeneous RBSN foam. Increasing the monomer content only from 15 to 20 wt% resulted in a threefold increase in the foam strength. The high porosity level of the foam which is above 70 vol% significantly affects the nitriding mechanisms and microstructures compared to those of dense RBSN ceramics. The maximum strength was obtained for the foams nitrided under N2–H2 atmospheres, and the nitriding temperature had a negligible effect on the foam strength when H2 is present in the atmosphere. α-Si3N4 is also the dominant phase in the microstructure in the presence of H2 regardless of the nitriding temperature. It was observed that β-Si3N4 can also be present in high quantities when N2 atmospheres are used. β-Si3N4 is present in the microstructures in two different morphologies including interlocking rods and angular grains. Each morphology forms based on a specific nitriding mechanism.

Keywords

Foam PMMA Monomer Content Nitriding Temperature PMMA Content 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

The authors gratefully acknowledge the financial assistance provided by National Science and Engineering Research Council of Canada.

References

  1. 1.
    Pigeon R, Varma A, Miller A (1993) Some factors influencing the formation of reaction-bonded silicon nitride. Mater Sci 28:1919–1936CrossRefGoogle Scholar
  2. 2.
    Huang Y, Zhou L, Tang Q, Xie Z, Yang J (2001) Water-based gelcasting of surface-coated silicon nitride powder. Am Ceram Soc 84(4):701–707CrossRefGoogle Scholar
  3. 3.
    Laarz E, Zhmud BV, Bergstrom L (2000) Dissolution and deagglomeration of silicon nitride in aqueous medium. Am Ceram Soc 83(10):2394–2400CrossRefGoogle Scholar
  4. 4.
    Omatete O, Strehlow R, Walls C (1990) Gelcasting of submicron alumina, sialon, and silicon nitride powders. In: The 37th sagamore army materials research, PlymouthGoogle Scholar
  5. 5.
    Alem A, Pugh MD, Drew RA (2014) Open-cell reaction bonded silicon nitride foams: fabrication and characterization. J Eur Ceram Soc 34(3):599–609CrossRefGoogle Scholar
  6. 6.
    Moulson A (1979) Review: reaction-bonded silicon nitride: its formation and properties. Mater Sci 14:1017–1051CrossRefGoogle Scholar
  7. 7.
    Lindley M, Elias D, Jones BF, Pitman K (1979) The influence of hydrogen in the nitriding gas on the strength, structure and composition of reaction-sintered silicon nitride. Mater Sci 14:70–85CrossRefGoogle Scholar
  8. 8.
    Dalgleish B, Pratt P (1975) The Influence of Microstructure on the Strength of Reaction-Bonded Silicon Nitride. Mech Prop Ceram 2(25):295–310Google Scholar
  9. 9.
    Evans AG, Davidge RW (1970) The strength and oxidation of reaction-sintered silicon nitride. Mater Sci 5:314–325CrossRefGoogle Scholar
  10. 10.
    Gazzara CP, Messier DR (1977) Determination of phase content of Si3N4 by X-ray difraction Analysis. Am Ceram Soc Bull 56(9):777–780Google Scholar
  11. 11.
    Ziegler G, Heinrich J, Wotting G (1987) Relationships between processing, microstructure and properties of dense and reaction-bonded silicon nitride. Mater Sci 22:3041–3086CrossRefGoogle Scholar
  12. 12.
    Jennings H (1983) Review: on reactions between silicon and nitrogen Part 1: Mechanisms. Mater Sci 18:951–967CrossRefGoogle Scholar
  13. 13.
    Danforth S, Jennings H, Richman M (1979) The influence of microstructure on the strength of reaction bonded silicon nitride(RBSN). Acta Metall 27:123–130CrossRefGoogle Scholar
  14. 14.
    Jennings HM, Dalgleish BJ, Pratt PL (1988) Reactions between silicon and nitrogen; Part 2 Microstructure. Mater Sci 23:2573–2583CrossRefGoogle Scholar
  15. 15.
    Petzow G, Herrmann M (2002) Silicon nitride ceramics. High Perform Non Oxide Ceram II 102:47–167CrossRefGoogle Scholar
  16. 16.
    Atkinson A, Leatt P, Moulson A, Roberts E (1974) A mechanism for the nitridation of silicon powder compacts. Mater Sci 9:981–984CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  1. 1.Mechanical and Industrial Engineering DepartmentConcordia UniversityMontrealCanada

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