Structure, mechanical and tribological properties of MoSe2 and Mo-Se-N solid lubricant coatings

Tomáš Hudec*, Vitalii Izai, Leonid Satrapinskyy, Teodor Huminiuc, Tomáš Roch, Maroš Gregor, Branislav Grančič, Marián Mikula, Tomáš Polcar

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Mo-Se-N films were prepared by pulsed direct current (DC) High Target Utilisation Sputtering (HiTUS) in reactive Ar + N2 atmosphere. Here, the effect of nitrogen doping was studied. MoSex film with Se/Mo atomic ratio ~ 2 exhibited polycrystalline structure and the lowest coefficients of friction (COFs) in humid air from 0.025 to 0.1 for loads in the range 2–45 N. Mo-Se-N coatings were deposited with N concentrations ranging from 1 to 40 at.%, whereas Se/Mo ratio varied from 0.6 to 2. Mo-Se-N coatings formed amorphous structures for the N contents above 7 at.% and increased hardness proportional with the N content up to 9 GPa. The addition of nitrogen also resulted in a general decrease in wear rate of two orders of magnitude when compared to pristine films while retaining a reasonably low coefficient of friction. Mo-Se-N films showed notable COF values in humid environment ranging from 0.22 to 0.015 when tested using loads from 2 to 45 N. The excellent friction properties of Mo-Se-N films were associated to the crystallisation of a MoSe2 tribofilm in the wear scar. Moreover, we showed that modern pulsed DC HiTUS technology represents a suitable way of producing thin films with a variety of elemental compositions and desired mechanical and tribological properties, even from sensitive, semi-conducting and extremely low thermally conductive MoSe2 targets.

Original languageEnglish
Article number126536
Number of pages12
JournalSurface and Coatings Technology
Volume405
Early online date30 Dec 2020
DOIs
Publication statusPublished - 15 Jan 2021

Keywords

  • Hardness enhancement
  • Low friction
  • Mo-Se-N
  • MoSe
  • Solid lubricant
  • Sputtering

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