Details

Autor(en) / Beteiligte

• Krysina, O.V.
• Ivanov, Yu.F.
• Koval, N.N.
• Prokopenko, N.A.
• Shugurov, V.V.
• Petrikova, E.A.
• Tolkachev, O.S.

Titel

Composition, structure and properties of Mo-N coatings formed by the method of vacuum-arc plasma-assisted deposition

Ist Teil von

• Surface & coatings technology, 2021-06, Vol.416, p.127153, Article 127153

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• A possibility in principle is shown for varying the elemental and phase compositions of nanocrystalline Mo-N coatings, synthesized using vacuum-arc plasma-assisted method, by changing the discharge parameters of the assisting gas plasma source at the constant pressure and composition of an Ar/N2 gas mixture. It is found out that an increase in the gas-to-metal ion current density ratio from 0 to 3 gives rise to a nearly twofold increase of nitrogen concentration in the coating of the Mo-N system. It is determined that as the discharge current is increased, the main metal (Mo) phase in the coating is replaced by a nitride phase with a nitrogen deficit (Mo2N), and then by a stoichiometric MoN phase. It is shown that the coatings formed in the plasma-assisted modes do not practically contain any metallic phase. With an increase in the nitrogen concentration the coating hardness increases by up to a factor of 1.3 (up to 36 GPa) and the wear resistance increases by about a factor of 2.4 (wear rate up to 2.1·10−7 mm3N−1 m−1) compared to the parameters of the coatings deposited in the regimes without plasma assistance. All coatings of the Mo-N system, synthesized in the plasma-assisted regimes, possess multiphase compositions: β-Mo2N, γ-Мо2N, δ-MoN. As the nitrogen concentration is increased, the volume fraction of δ-MoN phase increases to 67%. At the maximum nitrogen concentration, the Mo-N coating structure becomes columnar (plate-like) in the entire coating volume. The MoN and Mo2N plates have nanometric sizes, they are parallel to each other and combined into alternating packs. All Mo-N coatings are nanostructured, with the average Mo2N(β + γ) and MoN crystallite sizes being 3–4 and 3–5 nm, respectively. •Application of an assisting gas plasma source for the formation of PVD Mo-N coatings•Influence of the gas ion current density on the nitrogen concentration•The phase composition and structure vs. the PA modes and nitrogen concentration•Influence of the phase composition and structure on the properties of Mo-N coatings