Abrasive wear resistance of ion-deposited hard-carbon films as a function of deposition energy

Hard-carbon layers were deposited on WC-Co hard-metal substrates using mass-separated ¹²C⁺-ion beams with ion energies varying between 10 eV and 2 keV. The abrasive wear resistance, hardness, density, and dc resistance of these films were measured as a function of ion energy. Coatings deposited at ion energies between 100 eV and 2 keV possessed the highest hardness, best wear resistance, and good adhesion to the substrate, whereas coatings prepared at ion energies E_i ≤50 eV suffered from poor adhesion. The resistance of the hard-carbon coating against the abrasive wear was found to be about 300 times better than that of a typical ceramic Al₂O₃. In addition, Vickers hardness 120±20 GPa, density 3.3±0.3 g/cm³, and dc resistance 2×10 ⁹ Ω cm were obtained. The hardness was found to remain unchanged after the thermal annealing up to 600°C.