Ablation Characteristics of Alumina and Zirconia Ceramics on Ultra-short Pulsed Laser Machining

Ultra-short pulsed laser manufacturing gives a unique route to ablate hard-to-machine materials and enables little thermal impact.A comparative study on an alumina-toughened zirconia (ATZ) composite and pure alumina is presented.Single-and multi-pulse ablation of 1030nm and 515nm wavelength with sub picosecond pulses reveal an abrupt increase of the material removal rate.Pockets with 5µm beam distance and 15 layers rotated by 23° are generated to attain the multi-pulse ablation rate.The threshold fluence gives 0.1J/cm 2 and 0.11J/cm 2 for green wavelength and the ATZ and alumina, respectively.Single pulse ablation with 7J/cm 2 energy density point to the sharp ablation limit and an electron microscopy assessment reveals a step-like behavior.Subsequent Raman spectroscopy studies prove the persistence of the tetragonal morphology of zirconia.These findings enable laser manufacturing of microstructures on ceramic specimen with a 2.5D and quasi-tangential strategy.