Diamond - like carbon coatings for tribological applications

Abstract

This paper presents studies on the morphology, mechanical and tribological properties of hydrogen-free diamond-like carbon (DLC) coatings deposited via magnetron sputtering under different bias voltages. Atomic force microscope (AFM), transmission electron microscope (TEM), Raman spectroscopy, nano-indentation and ball-on-disc tribotest were employed to characterize the deposited coatings. Diamond-like carbon coatings had very smooth surface with the roughness (R_a) of less than 3.5 nm (for 1.2 mm -thick coatings on Si wafer). Under high bias voltage, superhard coatings with hardness of more than 30 GPa were obtained.The self-lubrication mechanism of diamond-like carbon combined with smooth surface resulted in very low coefficients friction of less than 0.15. Magnetron sputtered diamond-like carbon show a big potential for tribological applications, especially, under dry or poorly lubricated conditions.