Surface morphology characteristics and ablation thresholds of silicon carbide ceramics by femtosecond laser irradiation

Femtosecond laser ablation technology can overcome the challenges associated with fabricating complex components and the low machining accuracy inherent in traditional processing of silicon carbide ceramics, showcasing its broad application potential. In this work, the effects of pulse number and polarized light state on the ablation threshold and morphology of ablation pits were systematically investigated. The variation in the ablation threshold could be divided into three stages as the number of pulses increases. The efficiency of multiphoton ionization under linearly polarized light was higher than that under circularly polarized light, resulting in a lower ablation threshold. The surface morphology of ablation pits induced by linearly polarized light predominantly exhibited periodic streak structures and an ordered assembly of nanoparticles. The growth rate of the diameter was lower than that of the depth of the ablation pit, resulting in the formation of a conical structure. Due to Coulomb explosion and the cavitation backflow effect, the ejected silicon and carbon underwent oxidation reactions outside the ablation pit. This investigation provides both theoretical frameworks and practical guidelines for femtosecond laser micromachining of SiC ceramic components.