Laser micromachining of Al₂O₃−TiC ceramics

Al₂O₃−34 wt.% TiC ceramics have been machined with a KrF (248 nm) excimer laser under normal atmosphere. In the initial steps of the irradiation process both the roughness and the removal rate present a strong variation with the number of pulses. After approximately 200 pulses the process reaches a stationary regime where the roughness and the removal rate become constant. Characterization of the machined areas by scanning electron microscopy showed that the variations in roughness and removal rate are related to the evolution of the surface topography of the samples. Also, as a consequence of laser irradiation, TiC and Al₂O₃are partially transformed into TiO₂, TiC_0.7N_0.3, and an Al–Ti solid solution.