Tribological properties of TiSiN thin films deposited by laser ablation

Abstract The simultaneous ablation of silicon and titanium targets in a nitrogen atmosphere was performed in order to obtain the ternary compound TiSiN. The study showed that the plasma density played an important role in determining the composition and properties of the deposited thin films. The plasma parameters were measured using a planar Langmuir probe. The laser fluence applied to the silicon target was varied and this changed the silicon plasma density. The results demonstrated that the deposition rate and the silicon content in the films strongly depended on the plasma density. The composition measurements showed that the silicon content changed from 6 to 29 at.% when the plasma density was increased from 1 × 10 19  m − 3 to 1 × 10 20  m − 3 . The silicon ion energy was fixed at ~ 160 eV. In order to determine the hardness, friction coefficient, wear resistance and adhesion of the coatings, the TiSiN films were deposited onto nitrided stainless steel substrates at low temperature (200 °C) and a working pressure of 1.33 Pa (Ar/N 2 60/40). The overall results showed that the film hardness varied between 24 and 34 GPa, the friction coefficient (in air) from 0.55 to 0.58 with a wear rate as low as 1.2 × 10 − 6  mm 3 /N m and the critical load of adhesion, measured by scratch testing, was between 30 and 64 N.