Chapter 30. Contact Fatigue Behavior and Gas Cell Thermal Wave NDE of Sintered Reaction Bonded Silicon Nitride
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1996 The American Ceramic Society
Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 17, Issue 3
How to Cite
Barla, J. R., Rose, D. N., Benci, J. E., Edler, J. P. and Lin, H. (1996) Contact Fatigue Behavior and Gas Cell Thermal Wave NDE of Sintered Reaction Bonded Silicon Nitride, in Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 17, Issue 3 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314821.ch30
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1996
Print ISBN: 9780470375426
Online ISBN: 9780470314821
- optical microscopy;
Silicon nitride is being evaluated for potential applications as structural components subjected to contact fatigue loading. A new testing and evaluation methodology for evaluation of Hertzian contact fatigue damage in ceramic materials has been developed and is described. Contact fatigue damage is induced in three test specimens simultaneously. The material investigated is Eaton Corporation's low cost E–Process Silicon Nitride.* Tests were conducted at several Hertzian stress levels to evaluate contact fatigue damage behavior. Gas cell thermal wave NDE was employed to study the induced subsurface damage. Damage behavior was also investigated using optical microscopy. Two specimens were evaluated in detail; one that was tested for 17,400 cycles, Pmax = 2700 N and one that was tested for 1 × 106 cycles, Pmax = 1800 N . The 2700 N specimen has a partial cone crack and contains a small concentration of vertical and shallow horizontal cracks. No evidence of a cone crack was detected on the 1800 N specimen. However, a larger concentration of horizontal microcracks at and just below the surface is present in this specimen, with particle debris in and around the surface contact area. Correlation of the optical microscopy observations with gas cell thermal wave NDE of the subsurface damage in these two specimens is discussed.