Abstract
Cr–Si–N thin films were deposited by pulsed DC reactive dual-magnetron sputtering using Cr and Si targets, while various currents applied to the Si target allowed one to vary the Si content (
C
Si) in the films. Microstructure, composition and mechanical properties were studied as a function of
C
Si using XRD, ERD-TOF and depth-sensing indentation. Three regions of
C
Si were distinguished: (i)
C
Si
<
2.3 at.%, where the grain size (
D) does not significantly change with increasing
C
Si; (ii) 2.3
<
C
Si
<
6.7 at.%, where
D decreases as
C
Si increases; and (iii) 6.7
≤
C
Si
≤
11.6 at.%, where a relatively rapid decrease of
D is observed with increasing
C
Si. We found that the hardness (
H) and the reduced Young's modulus (
E
r) of the films reached maximum values of
H
~
24 GPa and
E
r
~
240 GPa for
C
Si
~
2.3 at.%. Based on the evolution of the microstructural and mechanical properties of the Cr–Si–N films, we propose to explain the hardening observed for
C
Si
<
2.3 at.% in terms of the solid solution mechanism rather than the nanocomposite formation.