The tribological performance of silver in aircraft turbine load cases

The primary focus of this work is to characterise the tribological behaviour of physical vapour deposition (PVD) coated silver bearing coatings under representative operational conditions in aircraft engines. Silver is a promising and well-known material for lead free journal bearings due to its excellent chemical and physical properties, such as heat conduction, ductility and its non-toxicity, but not comprehensively investigated for many potential tribological applications. The silver coating was tested in mixed friction, hydrodynamic friction and deficient lubrication against polished steel counterparts. In comparison to reference bearing materials silver showed a good damage tolerance in emergency operation scenarios by virtue of its ductility and heat conductive properties.