For metal-containing carbon films a wide range of application is envisaged, ranging from wear protection due to their tribological properties to electronics due to their electric and optical properties. Our interest is based on having well-characterized material for investigating the reduction of the chemical erosion of metal-doped carbon materials by hydrogen impact and elucidating underlying mechanisms. The chemical erosion is the main drawback for using carbon materials in future fusion devices like ITER.
The characterization on nanometer scale is essential for getting an understanding of the behavior of metal-containing carbon films in their application. Therefore, we characterize films produced by magnetron sputter deposition with floating potential in respect to composition, morphology, phase and structural ordering by thermal treatment and their chemical erosion by hydrogen impact.
Annealing up to 1300K of metal-doped (Ti, V, W, Zr) amorphous carbon layers with metal content up to 20 % leads to carbide formation and grain growth (several nm). Composition, distribution and diffusion of the metal in the carbon are investigated by Rutherford backscattering spectroscopy. X-ray absorption spectroscopy shows how the local atomic environment of the metal and carbon is affected by thermal treatment up to 1300 K.
In order to extent the list of characterized properties, the hardness in dependence of dopant type (V, Zr), dopant concentration (<18 at %) and annealing temperature (<1300 K) were investigated. The experimental boundary condition of film thickness (200-1800 nm) and substrate (Si, SiC, Cu, SiO2) were varied. The pure carbon film has a hardness of 12 GPa, which is always slightly increased up to 15 GPa by the doping. The annealing to 1300 K leads to a slight decrease of the hardness of the pure carbon film (11 GPa) and increase of the metal-containing ones (17 GPa).
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