Dynamical decohesion of TiN films induced by pulsed laser irradiation: in-situ photo-diagnstics and evaluation

Abstract

A new technique about evaluation of the adhesion strength of the film on the metallic substrate is presented in this article and the mechanism ofdynamic decohesion induced by the directed pulsed laser irradition forming is investigated elementarily from the theory. The procedure of laser-induced decohesion of TiN layers on SUS3O4 stainless steel has been investigated by means of in-situ laser interference ultrasonic measurements. The experiments were carried out by using a ?=532nm, ?=8ns (FWHM ) laser pulses irradiating the TiN film on the metallic substrate with a series of energy densities. The damage degree and dynamical procedure have been studied as a function of the energy density of laser pulses. The results demonstrate that interferometer measurements are a suitable non- invasive in-situ diagnostics tool for the assessment of the damage of the films that additionally provide valuable information conceming the process dynamics. Such results indicate that the dynamic decohesion procedure of the films is the most likely mechanism responsible for the laser-induced spallation process. At last the adhesion of the films on the metallic substrate are evaluated quantitatively.