Laser adhesion test: A tool for bond strength test using high-pressure shock induced by laser Available to Purchase

This paper deals with the LASAT technique (LASer Adhesion Test) developed in order to become a non-intrusive bond strength test for coatings. This technique consists in irradiating target (substrate+coating) with a laser in GW/cm² range to generate high-pressure shock wave (GPa), which the propagation can lead to the interface debonding and/or material spallation. Experimentally, a Doppler laser interferometer (Velocimetry Interferometer System for Any Reflector) measures the velocity time history at the rear surface. This velocity profile allows debonding and spallation detection. This paper presents our last results concerning this technique. Applied to Ni cold spray coating on Cu substrate, physical mechanisms of shock wave propagation are studied in using 1D SHYLAC (Simulation HYdrodynamique Lagrangienne des Chocs) code. Calculations reproduce velocity profile even for debonding with typical criteria for spallation. Results show also the brittleness of the coatings compared to the interface.