STUDY OF STRUCTURE AND MECHANICAL PROPERTIES OF TETRAHEDRAL AMORPHOUS CARBON FILMS DEPOSITED AT VARIOUS DISTANCES BETWEEN THE SOURCE AND THE SUBSTRATE

The coatings based on tetrahedral amorphous carbon were deposited through the diaphragm of 27 mm diameter on silicon substrates by a pulsed cathode-arc source at three different distances between the source and the substrate: 150, 215 and 265 mm. The structure and mechanical properties of the produced tetrahedral amorphous carbon films were studied using Raman spectroscopy and nanoindentation. The results showed that as the source-substrate distance increases, the structure of the films changes. The decrease in the concentration of ordered aromatic rings in Csp² cluster and the increase in the concentration of chain groups. The maximum values of nanohardness and Young's modulus are attained at the distance of 150 mm between the source and the substrate and are 21 GPa and 197 GPa, respectively. With the increase in the distance to 265 mm, these values decrease to 16 GPa and 177 GPa, respectively. Probably, at a close distance from the pulsed source, more closely packed structures are formed in the coatings, which affect the higher nanohardness. It is assumed that the formation of the coating structure depends on the source-substrate distance and is determined by the energy and spatial parameters of the pulsed plasma flow.

pulsed cathodic arc deposition, tetrahedral amorphous carbon films, Raman spectroscopy, nanohardness, Young’s modulus, nanoindentation

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