Mechanical properties of homogeneous and nitrogen graded TiN thin films

• Published in: Thin solid films 2020-09, Vol.710 (C), p.138268, Article 138268
• Main Authors: Silva, Felipe C., Tunes, Matheus A., Sagás, Julio C., Fontana, Luis C., de Lima, Nelson B., Schön, Cláudio G.
• Format: Article
• Language: English
• Subjects: Ceramics; Characterization; Coatings; Fracture behavior; Stress measurements; X-ray analysis
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2020.138268

•Variable N2 flow rate during deposition allows obtain functionally graded films.•Graded and homogeneous films show different preferred growth orientation.•Critical interface shear strength of homogeneous films is larger.•Film hardness increase with bias in both films.•Nanoscratching tests show that delamination load is larger in graded films. Coating of metallic industrial parts with titanium nitride (TiN) is widely used with the aim to improve the mechanical and tribological properties of these parts. In the present work, TiN films were deposited via grid-assisted magnetron sputtering on aluminium substrates. The films were grown under different substrate bias voltage (-40, -75 or -100 V) and two different modes of nitrogen supply during deposition (constant and variable), resulting in homogeneous and N-graded films. The results of tension fractures observed in situ were correlated with the film microstructure and residual stress levels obtained through grazing incidence X-ray diffraction measurements. Elastic properties of the films were analysed via nanoindentation and adhesive properties were investigated by nanoscratching tests. Results show that the delamination load of the graded films is higher than in the homogeneous counterparts, suggesting the graded film have improved tribological properties.