Engineered DLC based Wear Resistant Coating For Extended Life Foil-Air Bearings

Foil/air bearings have the benefit of negligible friction and wear once sufficient airflow is obtained; however, during spin up and spin down these bearings are subject to contact with the rotating surfaces upon which they act and thus are subject to frictional losses and wear. Modern air-cycle machines (ACMs) depend on solid lubricant based coating materials such as polyimide coatings to protect the foil bearing during these brief periods of contact, but these coatings fail prematurely and require frequent inspections.Nokomis will produce a material coating based off diamond-like carbon (DLC) that will achieve hardness values and wear properties near that of diamond and provide up to an order of magnitude reduction in the coefficient of friction (COF) as compared to the industry leading polyimide coatings. This lower COF will significantly reduce energy-loss during spin up, and also significantly reduce the magnitude of the temperature spikes seen during unintentional contact experienced during operation. The result will be a long lasting coating solution that is chemically and process engineered for exceptional thermal stability in the temperature region of 0 F to over 1000 F and possibly up to 1600 F.