Laser ablation and LIPSS formation at static and dynamic multi-pulse regime on protective Al₂O₃/TiAlN coating

The study of ablation and the laser-induced periodic surface structure (LIPSS) creation during the static and dynamic ultrafast laser (UFL) processing of the Al₂O₃/TiAlN protective coating is reported. The static irradiation was done with 10 successive pulses while scanning irradiation was performed with sample scanning. The laser ablation was studied by analysis of the surface morphology and elemental composition. The selective ablations manifest as circular craters or lines/micro-channels. The borders are very sharp without debris and hydrodynamic features. LIPSSs were formed at the bottoms of craters and microchannels. The periodicity of the created LIPSSs has shown a trend of increase with the pulse energy. Depending on the applied laser fluence the elemental composition in the centre of the craters confirmed the complete removal of the Al₂O₃ layer and partial ablation of the second TiAlN. The Al₂O₃ layer and part of TiAlN were ablated in micro-channels too.