ADVANCES in WEAR RESISTANT CARBON-BASED COATINGS for AEROSPACE COMPONENTS

Many aerospace components have to be protected against wear caused by abrasion, sliding, fatigue and fretting. More specifically, parts used in the flight control system, landing gear and aircraft engine platform (for example actuation parts , bearings and hydraulic systems) are coated to reduce friction, increase reliability of the systems and reduce maintenance efforts. Carbon-based coatings deposited by PVD (physical vapor deposition) or PECVD (plasma-enhanced chemical vapor deposition) are perfectly suited to this task for temperatures up to 500°F. With their low roughness, low coefficient of friction and high hardness, these thin films are an excellent alternative to hard chromium plating for many applications on different base materials. Many types of carbon coatings are available on the market, ranging from metal-containing hydrogenated amorphous carbon (ex. a-C:H:W or WC/C) to so-called tetrahedral amorphous carbon (ta-C). Each type has its own advantages and the versatility of this material family allows to cover an impressive range of requirements. Based on tribology and wear investigations, an overview will be given on the properties of various carbon-based films. Recent advances in the deposition of very hard and smooth carbon coatings by high power impulse magnetron sputtering (HIPIMS) will also be highlighted.