USA As Represented by Secretary of the Navy

David P Lascurain

Indranath Dutta

A Constant-Depth Scratch Test (CDST) technique to quantitatively determine he shear strength of interfaces between thin metallic or non-metallic films and metal or ceramic substrates is revealed. The test overcomes two problems associated with other types of scratch tests, namely the instrumental complexity required for real-time detection of interfacial failure, and the inability to quantify interfacial strength. These problems are circumvented by maintaining a constant depth during scratching through the coating and the substrate, monitoring the horizontal and vertical forces to sustain the constant depth scratch, and finally by using a model to analyze the test results to quantify the interfacial shear strength. Unlike other scratch tests, this test is capable of measuring interfacial shear strength as a function of position on the film-substrate sample.

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North Charleston, SC, United States of America

David P Lascurain