Surface Modifications of carbide ceramics induced by pulsed laser treatments

It is well known that sintered ceramics are very hard and difficult materials to process and machine by traditional methods. An easy and available solution seems to be a pulsed laser treatment, under appropriate experimental conditions (pulse duration and energy, radiation incidence angle, working atmospheres, etc.). In these experiments, in order to modify the structure and morphology of the surface, polycrystalline sintered SiC substrates were irradiated with an ArF ( D 193 nm; h D 6:4 eV; D 30 ns) pulsed laser, at different fluences and at grazing incidence angle. Since it is well known that laser irradiation can produce both a dissociation of surface compounds and a high level of amorphisation (owing to very rapid cooling of melted material) different working atmospheres (Ar or O2 or CH4) and substrate heating ( 700 C) have been used, with the aim of confining and controlling any chemical and physical transformation produced by laser-material interaction. Morphological and structural modifications have been studied by SEM=EDAX microscopy. Surface chemistry has been analysed by Raman spectroscopy. Changes in surface roughness have also been quantified by AFM microscopy.