Modification of multilayered TiAlN/TiN coating by nanosecond and picosecond laser pulses

Abstract

A multilayered TiAlN/TiN coating deposited on H11 work-steel was irradiated by a TEA CO(2) laser (ns pulses) and a Nd:YAG laser (ps pulses), and the effects compared. The coating was 2.17 mu m thick and consisted of 45 layers. The laser-induced modifications showed dependence on laser pulse duration, pulse count and laser wavelength. The conditions for coating ablation in both cases were determined. The experiment has revealed laser-induced periodic surface structures (LPSS) on nanometre and micrometre scales, depending on the laser wavelength used. Sample surfaces were characterized before and after laser irradiation by an optical microscope, scanning electron microscope (SEM), focused ion beam (FIB) microscope and profilometry.