Etude des mecanismes de nitruration du titane massif et des films minces de titane, dans un reacteur plasma basse pression hors equilibre, en atmosphere d'ammoniac

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

X-Ray and UV Valence Band Photoemission of Carbon Films

The widely differing properties of amorphous C films originate from the different s-p hybridization schemes possibly occurring in the C-C bond. For the study of such systems, an approach is suggested that provides direct access to these different types of s-p hybridization via a separate mapping of the s and p partial Density Of States (DOS) contributing to the total Valence Band (VB) DOS in C materials. Both X-Ray and UV excited VB spectra are needed to this end: the dependence of photoionization cross-sections on photon energy makes in fact X-Ray excited VB Photoemission essentially a probe of the s-DOS and UV excited VB Photoemission essentially a probe of the p-DO

Carbon effect on the phase structure and the hardness of r.f. sputtered zirconia films

Thin films of zirconia-carbon (ZrO2-x-C) were deposited by RF magnetron sputtering, on both polycarbonate and cemented-WC substrates. Two separate targets of monoclinic ZrO2 and graphite were used and a composition range was selected from 0 to ≈ 30 at.% carbon. The C-containing films resulted in a composite structure, which consisted of a zirconia phase coexisting with an amorphous carbon phase. A tetragonal zirconia phase was found in films containing 10-30 at.% carbon, while films of pure zirconia grew in the monoclinic phase. The tetragonal phase of zirconia coincided with the presence of compressive internal stresses in the films, which increased with increasing C content. As a consequences of the microstructure induced by the presence of carbon, the ZrO2-x-C films resulted in a stronger surface hardening of the polymeric substrates than the pure zirconia films did

Ar+-Implantation Effects on the Interfacial Properties of the WC/TI-6Al-4V System

This work reports on Ar+-implantation effects on structural, compositional and mechanical properties of the WC/Ti-6Al-4V system interface. The WC films were deposited by r.f. magnetron sputtering on Ti-6Al-4V substrates and then implanted at the film-substrate interface with Ar+ ions at 160keV. Two parameters have been varied in the implantations: the ion dose, F (F varying in the 1x1016-2X1017 atoms cm-2 range) and the sample temperature, T (in the ranges 298-333K and 393-463K). X-Ray diffraction measurements indicate that ion implantation induced the formation of a new phase, which can be identified as (Ti,W) C1-x or, more probably, W2(C,O). In Auger concentration depth-profiles, a large broadening of the interface was observed as a consequence of the implantations. Scratch tests indicate a small increase in film substrate adhesio