Chapter 47. Laser Scattering characterization of Subsurface Defect/Damage in Silicon-Nitride Ceramic Valves
- Edgar Lara-Curzio,
- Michael J. Readey
Published Online: 26 MAR 2008
DOI: 10.1002/9780470291191.ch47
Copyright © 2004 The American Ceramics Society
Book Title
28th International Conference on Advanced Ceramics and Composites B: Ceramic Engineering and Science Proceedings, Volume 25, Issue 4
Additional Information
How to Cite
Sun, J. G., Zhang, J. M. and Andrews, M. J. (2008) Laser Scattering characterization of Subsurface Defect/Damage in Silicon-Nitride Ceramic Valves, in 28th International Conference on Advanced Ceramics and Composites B: Ceramic Engineering and Science Proceedings, Volume 25, Issue 4 (eds E. Lara-Curzio and M. J. Readey), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291191.ch47
Publication History
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 2004
Book Series:
ISBN Information
Print ISBN: 9780470051528
Online ISBN: 9780470291191
- Summary
- Chapter
- References
Keywords:
- niobium-doped lead zirconate-titanate composition;
- lower porosity ceramic;
- solid matrix;
- spherical shell;
- volume strain
Summary
An automated laser-scattering system for nondestructive evaluation (NDE) was developed to scan silicon-nitride engine valves for distributed subsurface defects/damage. The technique is based on a cross-polarization detection method that measures only the optical scattering from the subsurface. The system utilizes two-rotation and two-translation stages to align and focus the laser beam on the valve surface during the entire scan, and the resulting two-dimensional scattering image is used to identify the location, size, and relative severity of subsurface defects. Laser-scattering images were obtained for two silicon-nitride valves made from NT551 (Norton-Saint Gobain) that were subjected to ambient-temperature cyclic-impact loads for 100 hours. These data were analyzed and compared with surface photomicroscopy results.