Caractérisation de couches minces dures élaborées par PVD.

Abstract

A series of Ti-Si coatings have been deposited by vacuum thermal evaporation technique, on Z200 steel and Si (100) substrates.180 mg of Ti powder and,4 at.%, 7 at.%, 11at.%, 17 at.% of Si grains were used as deposition source. XRD, SEM were employed for structural and morphological study of the films, nanoindentation hardness testing test was used to evaluate the mechanical properties, the corrosion behaviors of the coatings were studied .The X-Ray Diffraction patterns reveal that all films are polycrystalline, the hardness and the Young’s Modulus increase firstly to achieve a maximum value 33 GPa, and 795 GPa then decrease smoothly with a further addition of Si to a weak value. A series of Ti-Si-N thin films with different Silicon content were deposited on Si (100) substrate by RF magnetron sputtering in an Ar-N2 gas mixture. The influence of Si content on the microstructural and mechanical properties of the as deposited Ti-Si-N thin films has been investigated by characterization techniques such SEM equipped with Energy Dispersive Xray spectroscopy (EDX) for determining the composition of the films, XRD for microstructural characterization and nanoindentation system for mechanical properties. The grain size was estimated by measuring the Full Width at Half Maximum experimental peaks. The results reveal that the residual stress built in the coating is compressive they increase with the silicon content. The hardness of the films increases also with Si contents, further adding of the Si decrease the hardness, the grain size decrease with increasing the silicon content.. TiSiC thin films were deposited onto steel stainless and Si (001) substrates by technique hybrid RF– PECVD, using Ti and Si targets, and methane gas. The gas flow of the carbon was varied to keep the pressure inside the deposition chamber 10%, 15%, 20%, 25%, and 35%. The effects of the carbon content on the morphological, structural, and mechanical properties of the as deposited coating were investigated. Results reveal that the surface morphology of the TiSiC coatings less dense, the diffractogrammes show that TiSiC coatings has a polycristalline, the grain size increase with increasing carbon quantities in the samples. Ti-Al, Ti-Al-N films were prepared by sputtering Rf. The influence of film thickness on residual stresses was studied. The analysis of the residual stresses by the device Rings of Newton, for different thicknesses shows the existence of a peak between 200 and 400nm. The monitoring of annealing at different temperatures of films coated with TiAl, TiAlN films shows that the thermal stability of these films is ensured up to 900 and 800 °C respectively.