Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Detection of Contact Damage in Ceramics by an Ultrasonic Method



H Ahn, Gerald V. Blessing, John A. Slotwinski, S Jahanmir


A pulse-echo ultrasonic technique consisting of focused normal-incident compressional waves was used for the detection and evaluation of surface and subsurface damage in micaceous glass-ceramic and silicon nitride samples. The damage was produced by indentation with a tungsten carbide ball. The nature of the damage was found to be material-dependent and was classified into two types: Hertzian cone cracks in the silicon nitride, and distributed subsurface microcracks in the glass-ceramic. While the cone cracks were visible on the surface as circular ring cracks, the distributed subsurface microcracks were not associated with any visible surface cracks. Both the cone cracks and the distributed subsurface microcracks were easily detected by the ultrasonic technique. In addition, the ultrasonic beam was focused to different depths below the surface of the glass-ceramic sample to probe the subsurface region containing the microfracture damage.
Journal of Materials Research
Vol. 13, No. 7


microfracture, Nondestructive evaluation, subsurface, Ultrasonics


Ahn, H. , Blessing, G. , Slotwinski, J. and Jahanmir, S. (1998), Detection of Contact Damage in Ceramics by an Ultrasonic Method, Journal of Materials Research (Accessed May 19, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created January 1, 1998, Updated February 19, 2017