Detection of delamination located at ceramic/metal jointed interface by scanning acoustic microscopy

This paper reports on the evaluation of three different techniques to detect delaminations at interfaces of ceramic/metal joints. The three techniques were optical microscopy, scanning electron microscopy and scanning acoustic microscopy. The ceramic/metal joints consisted of plates of silicon nitrate and steel jointed with copper at the interface. The delaminations were introduce by a micro- Vickers indentor. Of the three techniques only scanning acoustic microscopy was successful in detecting the delamination. The V(z) curve technique was used to measure values for the surface acoustic wave velocity along the interface and for the defective specimens showed evidence of residual stress. Thus this study present useful guidelines in discriminating between good and defective ceramic/metal joints with scanning acoustic microscopy emerging as the most useful tool.