High-Speed Thermography of Thin Metallic Coatings

A high-speed infrared array camera was used to perform pulsed video thermography on metallic MCrA1Y coatings on a Ni-base alloy with thicknesses in the range of 37 to 130 microns. A flash lamp with controllable pulse duration was used. Delaminations at the interface of a 310 mu m thick copper layer on aluminium nitride ceramic could be observed. The thermal decay curves were modeled considering the measured temporal profile of the excitation light. The results were verified by high-frequency ultrasound measurements at 50 to 80 MHz.