The effect of oil type on blister formation in carbon-graphite mechanical seals

Blisters that are observed on carbon-graphite seal faces are created by a f racture process that derives from viscous friction forces present at the in stant that relative rotation begins between seal faces. High speed data acq uisition of shaft torque and shaft rotation data was used in this study to measure breakaway torque for different types of oils that were present betw een seal faces at startup. Synthetic polyalphaolefin oils create higher tra ction forces and a larger number of blisters than do mineral oils of compar able viscosity.