Gas turbine engine oil additives for advanced bearings - advanced steels

New oil additive chemistry is needed to lubricate corrosion resistant bearing steels, including ceramic rolling elements. Combining lubrication attributes of polyol ester basestock blends with innovative additive formulations provide opportunities forenhanced lubrication of new bearing materials as well as conventional materials. The oil and additive formulation strategy involves blending surface lubrication mechanisms, including adsorption, near-surface viscosity enhancement and reaction chemistry.Additives include thiadiazole chemistry, phosphorus and non-phosphorus chemistry. Feasibility is conducted with a supporting team of oil and additive suppliers with an engine company providing focus for materials and operating requirements. An iterativetesting and formulation strategy will use a modified load capacity oil qualification test, unique to the small business. Enhanced surface viscosity effects will be measured using 3-D ultra-thin-film measurements with optical interferometry. An existingload capacity database for qualified oil products will be used to judge feasibility and performance margin. Corrosion is a major cause of bearing rejection and failure. New oil chemistry compatible with corrosion resistant and ceramic bearing materialswill significantly improve the performance margin and lifecycle cost of JSF and other military engine systems. These advanced materials and lubricants have immediate spin-off to commercial engines, automotive and industrial applications, including greaselubricated systems.