A complete phase distribution map of the laser affected zone and ablation debris formed by nanosecond laser-cutting of SiC

Laser cutting of silicon carbide (SiC) poses significant challenges due to its extreme hardness and thermal resistance, necessitating high energy input and often leading to extensive melt-zone formation and collateral damage. This study optimizes nanosecond laser cutting of SiC by systematically investigating phase transformations, melt-zone formation, and debris deposition, offering a cost-effective alternative to femtosecond laser systems. Using Raman spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy, we construct a comprehensive phase distribution map of the laser-affected region, revealing key material transformations. Our results demonstrate that material removal is confined to a narrow central fissure. Meanwhile, the surrounding melt zone consists of phase-separated amorphous silicon (a-Si) and amorphous carbon (a-C). Lateral crevasses mark the interface between the melt zone and the unmodified SiC substrate. We further explore the influence of atmospheric conditions (oxygen, air, and argon) and laser pulse parameters (pulse width and repetition rate) on melt-zone formation and cutting efficiency. Oxygen-rich environments expand the melt zone and yield oxygen-rich debris, while inert atmospheres suppress oxidation, forming carbon-rich debris with less material loss. Shorter pulse widths enhance material removal while reducing melt-zone expansion, supporting a mechanistic framework in which sequential multiphoton absorption drives ablation while photothermal effects govern melt-zone formation. This study provides critical insights into optimizing nanosecond laser cutting of SiC, offering practical strategies for achieving high-precision cuts with less thermal damage and material waste. These findings contribute to advancing industrial laser machining of SiC, making high-precision, low-cost processing more accessible and efficient.