Properties of TiSiN coatings deposited by hybrid HiPIMS and pulsed-DC magnetron co-sputtering

• TiSiN coatings were processed for the first time by a hybrid HiPIMS and PDCMS deposition technique.
• The microstructure evolved from solid solution to biphasic nanocomposite.
• The Si augmentation permitted a microstructure refinement.
• The Si content determined the final mechanical-tribological properties.
• The oxidation resistance was enhanced by increasing the Si content.

TiSiN nanocomposites coatings were synthesized for the first time by a hybrid deposition technique where high power impulse (HiPIMS) and pulsed-DC (PDCMS) magnetron co-sputtering were used for Ti and Si deposition respectively in an Ar + N2 atmosphere. For the Ti target, the deposition parameters were fixed, while the current applied to the Si target ranged from 0 to 0.9 A. Thus, the Si content in the films was adjusted from 0 to 8.8 at.% Si to allows tailoring of microstructure and mechanical properties. TiSiN grain sizes decreased from ∼41 to ∼6 nm as the coatings became more siliceous. The hardness increased from 20 ± 0.41 to 41.31 ± 2.93 GPa when the Si concentration rose from 0 to 4.4 at.% Si, but beyond this last value, hardness degrades reaching 36.1 ± 2.21 GPa at 8.8 at.% Si. The wear behaviours evaluated by ball-on-disc tests were correlated with the Hardness/Young's modulus ratio. Moreover, the silicon enhanced the oxidation resistance and the least hardness deterioration was found in the sample with the higher silicon content (8.8 at.% Si) after a thermal annealing in air (2 h/700 °C).