Measurement of the local displacement field generated by a microindentation using digital speckle pattern interferometry and its application to investigate coating adhesion

This paper presents a technique to investigate the adhesion of thin coatings which combines digital speckle pattern interferometry and an indentation test. The proposed approach is based on the measurement of the local displacement field produced by a microindentation introduced on the coated surface of a specimen. It is experimentally demonstrated that the buckling of the coating generated by the microindentation depends on its adhesion to the substrate. Experiments carried out in specimens with different conditions in the coating–substrate interface show that digital speckle pattern interferometry can be used to determine the size of the buckled region and to give a measurement of the coating adhesion strength.