The observation and Raman analysis of the surface of a PET polymer after the impact of an aluminium particle, combined with thermal modelling, have shown the presence of a zone with modified crystallization. This heat affected zone, with a thickness of a few microns, has different shapes depending on the geometry of the splat particle which is at its origin. This is the sign of a sharp temperature increase followed by a very rapid cooling. As a result, the proposition of crystallized phase is gradually decreased, and an amorphous phase is formed in a thin layer close to the surface. These results have been used to develop a protective plasma spraying technique for the coating of organic parts.

The tribological behaviour of Ti/TiN amorphous nanometric multilayers is reported in comparison with that of single Ti and TiN layers, in order to study the wear mechanism of nanostructures submitted to that one may call “macroscopic loading”. Ti/TiN nanolayers were deposited onto Si substrate by high vacuum diode r.f. sputtering assisted by in-situ kinetic ellipsometry. Transmission Electron Microscopy (T.E.M.) characterization exhibited the multilayered structure of the films, ascertained by grazing angle X-ray reflectometry and ellipsometry. Sliding wear tests against alumina in dry air showed the ceramic-typed behaviour of the multilayers, the wear of which was partly governed through a microfracture mechanism. Their wear lifetime was found to be higher than that of Ti and TiN single layers and increased with the number of layers.