Correlation of Thin-Film Bond Compliance and Bond Fracture Resistance

Abstract

<p>The integrity of the interfacial bond between a coating and its substrate is of primary importance for any application. A technique for the quantitative nondestructive measurement of the bond fracture energy is essential for evaluating bond integrity. Scanning acoustic microscopy (SAM) provides a method for making localized measurements of film dis-bonds and film bond compliance based on the changes in the surface acoustic wave velocity in the layered medium. The results of these measurements for chrome/gold and gold films on glass substrates are summarized. The compliance of the bond and its fracture energy can be correlated in some film systems. An experiment to determine if this correlation exists for chrome/gold and gold films on sapphire substrates is described. Results of such an experiment would provide an empirical correlation between surface acoustic wave velocity measurements and the fracture energy of the film. The results of an experiment to measure the fracture energy of the interfacial bond between a gold film and the sapphire substrate are described.</p>