Chapter 13. Correlation of Processing and Sintering Variables with the Strength and Radiography of Silicon Nitride

  1. William Smothers
  1. William A. Sanders1 and
  2. George Y. Baaklini2

Published Online: 27 MAR 2008

DOI: 10.1002/9780470320341.ch13

10th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 7, Issue 7/8

10th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 7, Issue 7/8

How to Cite

Sanders, W. A. and Baaklini, G. Y. (1986) Correlation of Processing and Sintering Variables with the Strength and Radiography of Silicon Nitride, in 10th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 7, Issue 7/8 (ed W. Smothers), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470320341.ch13

Author Information

  1. 1

    NASA-Lewis Research Center, Cleveland, OH 44135

  2. 2

    Cleveland State University Cleveland, OH 44115

Publication History

  1. Published Online: 27 MAR 2008
  2. Published Print: 1 JAN 1986

ISBN Information

Print ISBN: 9780470374672

Online ISBN: 9780470320341

SEARCH

Keywords:

  • silicon nitride;
  • flexural;
  • accomplishments;
  • x-radiography;
  • columnar

Summary

A sintered Si3N4 -SiO2 - Y2O3 composition, NASA 6Y, was developed that reached four-point flexural average strength/standard deviation values of 857/36, 544/33, and 462/59 MPa at room temperature, 1200d̀ and 1370 d̀C, respectively. These strengths represented improvements of 56, 38, and 21 % over baseline properties at the three test temperatures. At room temperature the standard deviation was reduced by over a factor of three. These accomplishments were realized by the iterative utilization of conventional X-radiography to characterize structural (density) uniformity as affected by systematic changes in powder processing and sintering parameters. Accompanying the improvement in mechanical properties was a change in the type of flaw causing failure from a pore to a large columnar β-Si3N4 grain typically 40–80 m̈m long, 10–30 m̈m wide, and with an aspect ratio of 5:1.