Article ID Journal Published Year Pages File Type
1659145 Surface and Coatings Technology 2010 11 Pages PDF
Abstract
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-W2C to β-WC1 − x. Further C enrichment leads to a nanocomposite structure of small WC1 − 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 WC1 − 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.
Related Topics
Physical Sciences and Engineering Materials Science Nanotechnology
Authors
, , , , ,