Improved Threaded Fastener Coatings for Turbine Engine Applications

Threaded fasteners used in turbine engine experience seizing/galling problems due to exposure at high temperature, corrosive environment and vibration. A research program is proposed that includes determination of the mode of failure of the currently used fastener-coating systems, and evaluation of novel coating materials and processes under simulated service conditions. A preliminary selection of coating materials based on the experience of an engine manufacturer is proposed. Initial screening of proposed coating materials will be conducted by using sputtered coatings. Other less-sophisticated methods will be investigated for coatings selected from sputtering experiments. The coated fasteners will be assembled and exposed to high temperature and vibration using the existing test facilities at Pratt and Whitney. A realistic screening test incorporating the environmental engine condition of temperature and vibration will be developed in Phase I in collaboration with Pratt and Whitney.