Physical properties of a-C: N films produced by ion beam assisted deposition

Abstract

Carbon films with up to 32 at. % of nitrogen have been prepared with ion beam assisted magnetron, using a N2+/N+ beam at energies between 50 and 300 eV. The composition and density of the films vary strongly with the deposition parameters. EELS, SXS, XPS, and IR studies show that these a-C: N films are mostly graphitic and have up to 20% sp3 bonding. Nitrogen is mostly combined with carbon in nitrile (C ≡ N) and imine (C=N) groups. It is shown by RBS and NDP that density goes through a maximum as the average damage energy per incoming ion increases. Positron annihilation spectroscopy shows that the void concentration in the films goes through a minimum with average damage energy. These results are consistent with a densification induced by the collisions at low average damage energy values and induced graphitization at higher damage energy values. These results are similar to what is observed for Ar ion assisted deposition of a-C films. The mechanical properties of these films have been studied with a nanoindenter, and it was found that the hardness and Young's modulus go through a maximum as the average damage energy is increased. The maximum of mechanical properties corresponds to the minimum in the void concentration in the film. Tribological studies of the a-C: N show that the friction coefficient obtained against diamond under dynamic loading decreases strongly as the nitrogen composition increases, this effect being more pronounced at low loads.

Improved capacitance characteristics of electrospun ACFs by pore size control and vanadium catalyst

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Mechanical and optical properties of diamond-like carbon thin films deposited by low temperature process

“…Such DLC is proven to possess more signal bonds shown in the figure. DLC with signal bonds of higher intensity will enhance mechanical properties like hardness, roughness and wear resistance [3,4]. In this study, a high Young's modulus of 124 GPa and a relatively high nanoindentation hardness of 12 GPa suggest that the DLC films deposited under pressure of 50 mTorr using Ar plasma contain a high percentage of sp 3 sites.…”

Application of Cathodic Arc Deposited Amorphous Hard Carbon Films to the Head/Disk Tribology

“…These films show the highest sp3 fraction for hydrogenated films of 75%, a hardness of 60 GPa, and a mass density of 2.9 g/cm3. Hydrogen and nitrogen containing films deposited by other methods such as variations of the sputter technique and plasma enhanced CVD have a lower sp3 fraction around 20-40%, a hardness of 15-35 GPa, an elastic modulus of 100-200 GPa, a mass density of 1.7-2.3 g/cm3, and a stress of 1-3 GPa [16,18,[19][20][21]25,26].…”