EFFECTS OF PULSE WIDTH ON CORROSION BEHAVIOR OF DIAMOND-LIKE CARBON COATINGS PREPARED ON THE SURFACE OF HIGH NITROGEN NICKEL-FREE STAINLESS STEEL

Abstract

Effects of different pulse widths on morphologies and corrosion resistance of diamond-like carbon (DLC) coatings prepared on the surface of high nitrogen nickel-free stainless steel (HNSS) were investigated. It was found that different pulse widths of 10, 15 and 20[Formula: see text][Formula: see text]s mainly affect the porosity and internal stress within the coatings. The energies of the implantation ions were decreased as the pulse width increase. The growth mechanism of the coating with the pulse width of 20[Formula: see text][Formula: see text]s was mainly surface diffusion, in which the coating was porous and prone to corrosion. With the decrease of pulse width, the growth mechanism was mainly sub-plantation. The DLC coating became dense and the corrosion resistance was improved significantly. However, with further decrease of pulse width, internal stress within the coating was also increased. The effect of stress corrosion cracking may decrease the corrosion resistance of the DLC coating with the pulse width of 10[Formula: see text][Formula: see text]s. The influencing mechanisms of the pulse width on corrosion resistance and growth mechanism of DLC coating on the surface of HNSS are also discussed.