Chapter 13. Correlation of Processing and Sintering Variables with the Strength and Radiography of Silicon Nitride
- William Smothers
Published Online: 27 MAR 2008
Copyright © 1986 The American Ceramic Society, Inc.
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
- Published Online: 27 MAR 2008
- Published Print: 1 JAN 1986
Print ISBN: 9780470374672
Online ISBN: 9780470320341
- silicon nitride;
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.