0000000000411175
AUTHOR
M. Girault
Modelling nanoparticles formation in the plasma plume induced by nanosecond pulsed lasers
International audience; Nanoparticles formation in a laser-induced plasma plume in the ambient air has been investigated by using numerical simulations and physical models. For high irradiances, or for ultrashort laser pulses, nanoparticles are formed by condensation, as fine powders, in the expanding plasma for very high pairs of temperature and pressure. At lower irradiances, or nanosecond laser pulses, another thermodynamic paths are possible, which cross the liquid-gas transition curve while laser is still heating the target and the induced plasma. In this work, we explore the growth of nanoparticles in the plasma plume induced by nanosecond pulsed lasers as a function of the laser irra…
Incorporation d'azote et d'oxygène dans les nanoparticules formées par traitement de surface laser de cibles métalliques dans l'air
International audience; Lors de l'irradiation de matériaux métalliques tels que l'aluminium, le fer ou le titane par un faisceau laser de courte durée d'impulsion (de l'ordre de la nanoseconde), il se forme une vapeur très énergétique et fortement ionisée appelée plume-plasma. A la fin de l'interaction, ce plasma se refroidit et se détend à des vitesses supersoniques. Des nanoparticules résultent de la condensation de cette vapeur métallique dans l'air, donc de la réactivité chimique avec les gaz réactifs de l'air tels que l'azote et l'oxygène. L'objectif de cette étude est de quantifier la quantité d'éléments légers afin de comprendre les mécanismes physiques mis en jeu dans le plasma, cré…
In-situ small-angle x-ray scattering study of nanoparticles in the plasma plume induced by pulsed laser irradiation of metallic targets
Import JabRef; International audience; Small angle x-ray scattering was used to probe in-situ the formation of nanoparticles in the plasma plume generated by pulsed laser irradiation of a titanium metal surface under atmospheric conditions. The size and morphology of the nanoparticles were characterized as function of laser irradiance. Two families of nanoparticles were identified with sizes on the order of 10 and 70 nm, respectively. These results were confirmed by ex-situ transmission electron microscopy experiments.