Effect of femtosecond laser parameters on TiC ceramic micro-hole drilling

Drilling micro-holes in TiC ceramic with femtosecond laser in different laser fluence and assisted gas pressure has been demonstrated. Scanning electron microscope (SEM), micrometer X-ray 3D imaging system (Micro-CT) and X-ray photoelectron spectroscopy (XPS) are used to investigate the morphology and chemical bonds of micro-holes. The results show that the circularities of micro-holes at the entry are not less than 99% when the laser fluence varies. The circularities of micro-holes at the exit increase as the laser fluence grows, then it tend to be stable. The maximum value of the circularity at the exit is 95%. The taper of micro-holes increases with the assisted gas pressure. When the laser fluence is 0.51 J/mm², the taper of micro-holes drilled with 0.3 MPa gas pressure is the best, its long axis taper is -0.13° and the short axis taper is 0.77°. C-C bonds and Ti-C bonds rupture while debris which contains metal Ti, Ti₂O₃ and TiO₂ forms around the micro-holes during laser drilling. Lastly, the mechanism of interactions between laser beam and materials is discussed.