Tantalum oxynitride thin films: Mechanical properties and wear behavior dependence on growth conditions

• Published in: Surface & coatings technology 2014-11, Vol.258, p.587-596
• Main Authors: Cristea, D., Crisan, A., Munteanu, D., Apreutesei, M., Costa, M.F., Cunha, L.
• Format: Article
• Language: English
• Subjects: Adhesion; Applied sciences; Contact of materials. Friction. Wear; Cross-disciplinary physics: materials science; rheology; Crystallinity; Engineering Sciences; Exact sciences and technology; Friction; Hardness; Materials; Materials science; Mechanical properties; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Methods of deposition of films and coatings; film growth and epitaxy; Oxynitrides; Physics; Polarization; Surface treatments; Tantalum; Tantalum oxynitride; Thin films; Wear; Wear behavior; Young's modulus
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2014.08.031

Tantalum oxynitride (TaNxOy) thin films were produced by magnetron sputtering. This work analyzes and compares the mechanical properties and the wear behavior of the films, taking into account the differences promoted by changes in composition and structure, caused by the variation of the partial pressure of the reactive gases (P(N2+O2)) and by the polarization of the substrate holder. Besides the change in composition, the variation of P(N2+O2) causes significant changes in the morphology and structure of the films. Those produced with low P(N2+O2) evidence a higher crystallinity and, in these conditions, the films exhibit hardness around 20GPa. Films produced with higher P(N2+O2) exhibit higher O content, are amorphous and the hardness is significantly lower. The substrate bias does not influence the adhesion of the films to the high speed steel substrate, but influences the mechanical properties, particularly the hardness, at low P(N2+O2) regime. Films with higher crystallinity exhibit higher hardness, but in the low P(N2+O2) regime, those who were produced with polarization are harder. Although some dependence may be established for set B films, the hardness is not as influent on the wear resistance of the TaNxOy films as the friction coefficient. •The increase of O content negatively influences the adhesion of TaNxOy films.•The increase of the non-metal reduces the hardness and elastic modulus of the films.•Films with low non-metal concentration, produced with substrate bias, are harder.•Non-amorphous films exhibit higher wear resistance.•Friction coefficient influences the wear behavior more than the hardness.