Femtosecond laser ablation of zirconia-based ceramic materials: From ablation mechanism to modelling of large-scale processing

Femtosecond laser ablation can offer a promising solution for precise and efficient processing of zirconia-based ceramics taking advantage of ultrafast photon-material interaction. However, due to the nonlinear nature of the process, the selection of the laser parameters in 3D processing is complicated, often leading to reduced efficiency or low material integrity. Here, we address this problem through static (D2) and dynamic (grooving) testing, establishing a comprehensive understanding of the femtosecond ablation behaviour of zirconia on micro- and macro- scales. The ablation threshold of zirconia shows a significant dependence not only on the irradiation history but also on the material temperature. While the processing efficiency can be increased, a critical interpulse duration or a high heat input can facilitate a melting regime, negating the advantages of pulsed laser ablation. Morphological evolution of the surface impacts the ablation behaviour further affecting the process efficiency. Additionally, zirconia semitransparency leads to the formation of nanopores compromising residual material integrity. Based on the analysis of these elementary ablation events, we built an ultrafast computational model, simulating the surface evolution during femtosecond laser ablation with various beam-surface kinematics. Validating the model on a 3D dental crown surface underscores its potential for computer aided design-manufacturing frameworks given its efficiency. • The ablation testing revealed micro- and macro heat accumulation effects in zirconia. • Upon the critical interpulse period the ablation mechanism shifts to severe melting. • Nanoporosity due to intergranular ablation in zirconia is linked to laser parameters. • The ultrafast computational femtosecond ablation model is introduced and validated.