Study of the flaking-off phenomenon on a jet Engine's shaft bearing using the thin layer activation technique

The Thin Layer Activation technique has been applied in order to study the flake-off phenomenon on a jet engine's shaft bearing. The external track of the bearing has been activated following the reaction ⁵⁶Fe(p,n)⁵⁶Co, over a depth of 80 μm. In spite of a very low activation level, the first signs of flaking-off were detected 30 min before any significant increase in the vibration level appeared. At that point, the mass of particles leaving the track was measured on line, with a precision of 0.2 mg.