A review of the mechanical tests for assessment of thin‐film adhesion

For any intended application of a film, its adhesion to the substrate is of primary importance for any practical utilization of the composite. However, it is difficult to measure this parameter quantitatively, especially when the adhesion is acceptable. In this paper, mechanical methods of obtaining quantitative data for adhesion are reviewed with special emphasis on the scratch testing technique. In this particular test, the critical load (normal force applied on a moving stylus responsible for debonding of the film) is a characteristic value of adhesion. Several methods of determining the critical load and its interpretation as it relates to adhesion, as well as the concepts and theory of the test, are discussed.