Chapter 43. Application of Laser Scattering to the Detection of Surface and Subsurface Defects in Si3N4 Components
- John B. Wachtman Jr.
Published Online: 28 MAR 2008
Copyright © 1994 The American Ceramic Society
Proceedings of the 18th Annual Conference on Composites and Advanced Ceramic Materials - A: Ceramic Engineering and Science Proceedings, Volume 15, Issue 4
How to Cite
Steckenrider, J. S. and Ellingson, W. A. (1994) Application of Laser Scattering to the Detection of Surface and Subsurface Defects in Si3N4 Components, in Proceedings of the 18th Annual Conference on Composites and Advanced Ceramic Materials - A: Ceramic Engineering and Science Proceedings, Volume 15, Issue 4 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314500.ch43
- Published Online: 28 MAR 2008
- Published Print: 1 JAN 1994
Print ISBN: 9780470375327
Online ISBN: 9780470314500
Silicon Nitride (Si3N4) ceramics are currently the primary materials of choice in structural applications because of their mechanical and thermal properties. However, the lifetimes of these ceramic components — especially those that experience contact fatigue (e.g., bearings) — are most affected by defects such as voids, inclusions, or microstructural variations in the surface or immediate subsurface (<200 μm) region. Thus, a technique is desired for the rapid detection and quantification of both surface and subsurface defects. Because Si3N4 can partially transmit visible (and IR) light, we have applied laser scattering to the analysis of various Si3N4 materials fabricated into several component shapes. Using polarization techniques to independently analyze surface and subsurface material, we have detected defects as deep as 100 um below the surface. Other methods such as X-ray CT and SEM analysis have further substantiated these results.