Hybrid laser ablation of Al2O3 applying simultaneous argon plasma treatment at atmospheric pressure
In this work, we present a hybrid laser-plasma ablation technique for material processing of ceramics. Atmospheric pressure argon plasma treatment as well as laser ablation and hybrid laser-plasma ablation experiments were performed on aluminium oxide in order to investigate the impact of the assisting plasma in terms of material removal efficiency and energy-related aspects. It was shown that by means of pure plasma treatment, surface roughness was decreased, resulting in an increase in surface energy and polarity, respectively. Further, by simultaneously applying a plasma beam at atmospheric pressure to a laser ablation process, the ablated area on the aluminium oxide surface was increased while the form error was partially reduced. Spectroscopic measurements of the ablation plume for pure laser ablation and laser-plasma ablation were performed. It was shown that with the assisting plasma, characteristic spectral lines of aluminium were intensified. Further, other Al-spectral lines that were not observed in the case of pure laser ablation were detected, corresponding to higher material removal owing to energetic synergies of both the laser ablation process and the assisting plasma.