Fretting Wear Elimination in Gear Box Housings

The development of the F-35 LiftFan has revealed the possibility of fretting between the fan input shaft bearing OD surface and the aluminum gearbox housing. A steel insert is currently used to provide protection against fretting of the gearbox housing. In order to provide an effective solution and reduce the overall weight of the F-35, “IBC Materials and Technologies” has developed an advanced tribological coating that will dramatically reduce fretting, wear and corrosion of the LiftFan gearbox housing, allowing elimination of the steel insert. The proposed solution is based on Plasma Electrolytic Oxidation (PEO) process that has been developed by IBC Materials and Technologies. The PEO-based Aluminum Oxide coatings will provide superior performance, extended life and lower processing costs compared with alternative methods, providing an opportunity for life cycle cost reduction for the F-35 engines. Phase I results demonstrated the coating will increase the fretting life 15.7 times, with growth capability to further increase fretting, corrosion, thermal protection, impact resistance and solid lubrication properties. In the Phase II program IBC will further optimize the coating for improved performance, demonstrate the repeatability of the coating process, and develop local adapters to form a sealed local electrolytic bath.