STRUCTURE AND PROPERTIES OF DLC LAYERS FOR INDUSTRIAL APPLICATIONS

Diamond-like carbon (DLC) layers based on amorphous carbon are used for wide range of applications, mostly for mechanical protection of various industrial components. As the properties of DLC layers are closely linked to their structure, we examined them at micro- and nanoscale by two independent microscopic techniques: Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) with a good agreement. We compared DLC layers grown on steel substrate and Si wafer and found similarly structured clusters with hundreds of nm in diameter and a certain difference in the density of nucleation centres for each substrate. The measurements of local mechanical properties by the AFM tip revealed that the Si wafer behaves as softer material compared to the growing DLC nanoclusters that also exhibit lower values in the map of the relative local friction coefficient. Finally, we observed changes in the Raman spectra of the DLC exposed to annealing at ambient conditions and found a gradual shift from the diamond phase to the graphite phase as a function of increasing temperature. At the highest temperature of 400 degrees C we observed the formation of tungsten oxide from an additional element contained in the multi-layer stack.