Chapter 1. Development of Water Based Processing of Silicon Nitride Materials

  1. Hua-Tay Lin and
  2. Mrityunjay Singh
  1. Kent Rundgren1 and
  2. Ola Lyckfeldt2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294741.ch1

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3

How to Cite

Rundgren, K. and Lyckfeldt, O. (2008) Development of Water Based Processing of Silicon Nitride Materials, in 26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3 (eds H.-T. Lin and M. Singh), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294741.ch1

Author Information

  1. 1

    Permascand AB PO Box 42 SE-840 10 Ljungaverk, Sweden

  2. 2

    Swedish Ceramic Institute PO Box 5403 SE-402 29 Göteborg, Sweden

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2002

ISBN Information

Print ISBN: 9780470375785

Online ISBN: 9780470294741

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Keywords:

  • granulation;
  • rheological properties;
  • flexure strength;
  • homogeneity;
  • densification

Summary

To strengthen the position of Si3N4 as a competitive material in structural applications, cheap raw materials as well as efficient and environmentally friendly processing routes are required. In this work, water-based processing of a medium-cost commercial Si3N4 powder (SICONIDE P95, Permascand AB, Sweden) was developed. This was done by planetary milling to improve the sintering performance and by freeze granulation to ensure high granule quality. Re-dispersing of a milled and freeze granulated/freeze-dried powder resulted in significantly improved rheological properties, enabling high solids-loaded suspensions (< 57 vol%). Adding sintering aids (6 wt% Y2O3 and 2 wt% Al2O3) prior to milling and pressing aids (PVA/PEG or latex/PEG) prior to freeze granulation gave excellent pressing performance and CIPed components, which sintered to nearly full density using GPS (Gas Pressure Sintering). The microstructures were characterized by a bimodal grain size distribution and negligible porosity. Mechanical data, flexure strength of 600–900 MPa, indicated possibilities of approaching material properties obtained with more expensive powders and processing routes. PVA/PEG was shown to be the more favorable pressing aid system compared to latex/PEG that gave lower strength.