Friction and wear of DLC films on magnesium alloy

Diamond-like carbon (DLC) films are well known for their high hardness, low friction and excellent wear resistance. Therefore, DLC film coating can contribute to improving mechanical and tribological properties of materials. DLC films have usually been deposited on super hard alloys. So far, few reports about DLC films deposited on soft materials have been published. In recent years, magnesium has been widely used because of its lightweight and ease of recycling. However, magnesium alloys are inferior in wear resistance and corrosion resistance. Therefore, it is necessary to improve these properties to use magnesium for more machine parts. DLC films were deposited on the magnesium alloy substrate by the plasma CVD method using radio frequency (RF). The friction and wear properties of the films were investigated under dry conditions, and in corrosive solutions of 3 mass% sodium chloride (NaCl), 0.05 normal hydrochloric acid (HCl) and 0.05 normal sodium hydroxide (NaOH) conditions. The process used to deposit the DLC coating was confirmed to be effective in decreasing the fiction coefficient and improving the corrosion wear resistance in 3 mass% NaCl and 0.05 normal NaOH solutions. However, DLC films showed poor corrosion wear resistance in 0.05 normal HCl due to the existence of pits in the films. (c) 2004 Elsevier B.V. All rights reserved.