Relationship between mechanical properties and coefficient of friction of sputtered a-C/Cu composite thin films

J. Musil, M. Louda, Z. Soukup, M. Kubásek

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)


The article reports on properties of a-C films containing different amount of Cu. Films were sputtered by unbalanced magnetron from a graphite target with Cu fixing ring in argon under different deposition conditions. Relationships between the structure, mechanical properties, macrostress σ and coefficient of friction (CoF) μ of a-C/Cu films sputtered on Si substrates were investigated in detail. Besides, a special attention was concentrated on investigation of the effect of a deposition rate aD of the a-C/Cu film on its hardness H and macrostress σ. Four main issues were found: (1) the addition of Cu into a-C film strongly influences its structure and mechanical properties, i.e. the hardness H, effective Young's modulus E* macrostress σ and CoF, and makes it possible to form electrically conductive films; here E* = E / (1 - ν2), E is the Young's modulus, and ν is the Poisson's ratio, (2) the hardness H and compressive macrostress σ of the a-C/Cu film decrease with increasing aD due to decreasing of total energy ET delivered to the film during its growth, (3) hard a-C/Cu films with low value of CoF (μ ≈ 0.1) can be sputtered at high deposition rates aD ranging from ~ 10 to ~ 80 nm/min, and (4) CoF decreases with increasing (i) hardness H and (ii) resistance of film to plastic deformation characterized by the ratio H3/E*2 but only in the case when compressive macrostress σ is low.

Original languageEnglish
Pages (from-to)1905-1911
Number of pages7
JournalDiamond and Related Materials
Issue number11
Publication statusPublished - 1 Nov 2008


  • a-C/Cu film
  • Composite
  • Friction
  • Mechanical properties
  • Sputtering

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Chemistry(all)
  • Mechanical Engineering
  • Physics and Astronomy(all)
  • Materials Chemistry
  • Electrical and Electronic Engineering

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