Plasma Nitrided + DLC: A Multifunctional Coating on Gray and Nodular Cast Irons
(Room Wabash 2)
13 May 16
10:20 AM
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10:40 AM
Tracks:
Protective, Tribological and Decorative Coatings
In the present study, the main critical factors affecting the production of high tribological performance coatings onto substrates containing near surface graphite were evaluated. Plasma nitriding followed by deposition of a hydrogenated Diamond Like Carbon film (a-C:H) onto gray and nodular cast iron substrates were carried out using a single thermal cycle. The surface topography evolution was evaluated via Scanning Electron Microscopy (SEM) and White Light Interferometry (WLI). Furthermore, the surface evolution after plasma nitriding of cast irons was carefully investigated via EDS line scans, XRD and microhardness profiles. This enabled a more in-depth understanding that endorsed previous phenomenological theories regarding this issue. Additionally, the tribological performance of multifunctional coatings was evaluated via durability tests in ambient air, which revealed friction coefficients as low as 0.06 during steady state lubrication regime for gray cast iron substrates, whereas the values where 0.14 for nodular cast iron substrates. By analysing interrupted tests for both materials with Raman spectroscopy, SEM, EDS and WLI, it was possible to correlate the production route, the surface topography and the coating characterization with differences in tribological performance between materials.