Surface modifications of carbide ceramics induced by pulsed laser treatments

It is well known that sintered ceramics are very hard and difficult materia ls to process and machine by traditional methods. An easy and available sol ution seems to be a pulsed laser treatment, under appropriate experimental conditions (pulse duration and energy, radiation incidence angle, working a tmospheres, etc.). In these experiments, in order to modify the structure a nd morphology of the surface, polycrystalline sintered SIC substrates were irradiated with an ArF (lambda = 193 nm, hv = 6.4 eV, tau = 30 ns) pulsed l aser, at different fluences and at grazing incidence angle. Since it is wel l known that laser irradiation can produce both a dissociation of surface c ompounds and a high level of amorphisation (owing to very rapid cooling of melted material) different working atmospheres (Ar or O-2 or CH4) and subst rate heating (similar to 700 degrees C) have been used, with the aim of con fining and controlling any chemical and physical transformation produced by laser-material interaction. Morphological and structural modifications hav e been studied by SEM/EDAX microscopy. Surface chemistry has been analysed by Raman spectroscopy. Changes in surface roughness have also been quantifi ed by AFM microscopy.