Effect of nitrogen content on microstructure and corrosion resistance of sputter-deposited multicomponent (TiNbZrTa)Nx films

SURFACE & COATINGS TECHNOLOGY

卷:404

Article

Shu, Rui¹  Paschalidou, Eirini-Maria²  Rao, Smita G.¹  Bakhit, Babak¹  Boyd, Robert³  Moro, Marcos Vinicius⁴  Primetzhofer, Daniel⁴  Greczynski, Grzegorz¹  Nyholm, Leif²  le Febvrier, Arnaud¹  Eklund, Per¹ 

[1] Linkoping Univ, Dept Phys Chem & Biol IFM, Thin Film Phys Div, Linkoping, Sweden

[2] Uppsala Univ, Dept Chem Angstrom, Uppsala, Sweden

[3] Linkoping Univ, Dept Phys Chem & Biol, Plasma & Coatings Phys Div, Linkoping, Sweden

[4] Uppsala Univ, Dept Phys & Astron, Uppsala, Sweden

关键词: Thin films;    Multicomponent nitride;    Magnetron sputtering;    TiNbZrTaN;    Corrosion resistance;   

DOI  :  10.1016/j.surfcoat.2020.126485

来源: Elsevier

【 摘 要 】

Multicomponent (TiNbZrTa)N-x films were deposited on Si(100) substrates at room temperature using magnetron sputtering with a nitrogen flow ratio f(N) [f(N) = N-2/(Ar + N-2)], which was varied from 0 to 30.8%. The nitrogen content in the films varied between 0 and 45.2 at.%, i.e., x = 0 to 0.83. The microstructure was characterized by X-ray diffraction and electron microscopy. The metallic TiNbZrTa film comprised a dominant bcc solid-solution phase, whereas a single NaCl-type face-centred cubic structure was observed in all nitrogen-containing films (TiNbZrTa)N-x. The mechanical, electrical, and electrochemical properties of these films varied with nitrogen content. The maximum hardness was achieved at 22.1 +/- 0.3 GPa when N = 43.0 at.%. The resistivities increased from 95 to 424 mu Omega cm with increasing nitrogen content. A detailed study of the variation of morphology and chemical bonding with nitrogen content was performed and the corrosion resistance of the TiNbZrTa nitride films was explored in 0.1 M H2SO4. While all the films had excellent corrosion resistances at potentials up to 2.0 V vs. Ag/AgCl, the metallic film and the films with low nitrogen contents (x < 0.60) exhibited an almost stable current plateau up to 4.0 V vs. Ag/AgCl. For the films with higher nitrogen contents (x >= 0.68), the current plateau was retained up to 2.0 V vs. Ag/AgCl, above which a higher nitrogen content resulted in a higher current. The decrease in the corrosion resistance at these high potentials indicate the presence of a potential-dependent activation effect resulting in an increased oxidation rate of the nitrides (present under the passive oxide film) yielding a release of nitrogen from the films. TEM results indicate that the oxide layer formed after this corrosion measurement was thick and porous for the film with x = 0.76, in very good agreement with the increased corrosion rate for this film. The results demonstrate that an increased nitrogen content in (TiNbZrTa)N-x system improves their mechanical properties with retained high corrosion resistance at potentials up to 2.0 V vs. Ag/AgCl in 0.1 M H2SO4. At even higher potentials, however, the corrosion resistance decreases with in- creasing nitrogen concentration for films with sufficiently high nitrogen contents (i.e. x >= 0.68).

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