Tailored synthesis of nanostructured WC/a-C coatings by dual magnetron sputtering

• Published in: Surface & coatings technology Vol. 204; no. 21; pp. 3490 - 3500
• Main Authors: Abad, M.D., Muñoz-Márquez, M.A., El Mrabet, S., Justo, A., Sánchez-López, J.C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2010; Elsevier
• Subjects: Amorphous carbon; Applied sciences; Coatings; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Friction; Hardness; Magnetron sputtering; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Nanocomposites; Nanocrystals; Nanomaterials; Nanostructure; Physics; Production techniques; Surface treatment; Surface treatments; Synthesis; Tungsten carbide; X-ray photoelectron spectroscopy; Tungsten carbide; Magnetron sputtering; Amorphous carbon; Nanocomposites; Friction; Hardness; Mechanical properties; Surface treatments; Amorphous state; Nanostructures; Coatings; Carbon; Sputtering; Magnetrons; Composite materials; Synthesis; Physical vapor deposition
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2010.04.019

Nanostructured coatings with variable contents of tungsten carbide (WC) and amorphous carbon (a-C) are prepared by controlling the sputtering power ratio using WC and graphite targets. XRD and TEM/ED analysis shows that increasing the C incorporation, the WC nanocrystalline phases evolve from γ-W 2C to β-WC 1 − x . Further C enrichment leads to a nanocomposite structure of small WC 1 − x crystals dispersed in a-C matrix. The a-C at.% is estimated by XPS analysis and correlated with the observed tribo-mechanical properties. The hardness and friction properties vary from hard/high friction (36–40 GPa; μ = 0.6–0.8) to moderate-hard/low friction (16–20 GPa; μ ∼ 0.2) coatings depending on the film composition. The transition point is found for a-C content of 10 at.%. This correlates with a change from nanocrystalline WC to nanocomposite WC 1 − x /a-C coatings. The overall study will help to understand the previous literature data and will serve as guide for a tailored synthesis of these WC/a-C nanocomposites.