Corrosion protection of carbon fibre reinforced aluminium composite by diamondlike carbon coatings

Carbon fibre reinforced aluminium exhibits poor resistance against electroc hemical corrosion in 3.5 wt-%NaCl solution, Diamondlike carbon (DLC) coatin gs provide properties which make them interesting materials for external co rrosion protection on metal matrix composites (MMCs). The electrochemical c orrosion behaviour of uncoated and DLC coated carbon fibre reinforced alumi nium was tested in 3.5 wt-%NaCl solution. It has been found that the pittin g potential is shifted significantly in the anodic direction and the corros ion current density is much lower due to the presence of the sealing DLC co ating. Additionally, scratch tests and SEM studies were carried out in orde r to characterise the adhesion of the DLC films on the heterogeneous MMCs, Reliable corrosion protection is connected with sufficient coating durabili ty under loading, In order to ensure sufficient loading capacity of the DLC coating under tribological conditions, wear tests were undertaken which re vealed a considerable improvement in wear resistance due to deposition of t he DLC coatings. MST/4373. (C) 2000 IoM Communications Ltd.