Gas turbine engine oil additives for advanced bearings - advanced steels

In order to meet new requirements for improved performance and longer life, engine manufacturers have investigated the use of new, advanced, high-chrome steels in engine bearings. The use of these advanced materials should allow for higher operating temperatures and higher speed capabilities, while reducing bearing corrosion and improving fatigue resistance. However, they have experienced significantly shorter life than anticipated in performance tests conducted using current gas turbine engine oils (GTOs). Their chemistry does not interact in the same way with the conventional aryl phosphate antiwear lubricant additives to form lubricious surface coatings. Under the Phase I program, METSS investigated the technical feasibility of developing new lubricant additives for corrosion-resistant high-chrome steels by evaluating a number of lubricant chemistries for their antiwear properties and their thermo-oxidative stability. Under the proposed Phase II program, METSS will optimize the performance of these new lubricant additives with regard to antiwear characteristics, corrosion resistance, thermal and oxidative stability, and deposit forming tendencies. Since GTO fluids are also used to lubricate conventional steels used in gear and bearing applications, special emphasis will be placed on additional tribology testing required to fully qualify the new lubricants for DoD requirements. The Phase II efforts will clearly define and support a viable path for technology commercialization and field implementation.