  This paper investigates the transition from abrasive to adhesive wear in
gross-slip fretting assuming contact oxygenation concept which suggests that
adhesion appears in the inner part of the interface if the di-oxygen partial
pressure is below a threshold value. In the lateral sides, where di-oxygen
molecules are sufficient, oxidation and abrasion prevail. To assess this
phenomenon, 34NiCrMo16 flat-on-flat contacts are tested. Contact oxygenation is
quantified using the ''oxygen-distance, '' parameter defined as the averaged
width of the external abrasion corona. Confirming this concept, decreases with
contact pressure and frequency but remains constant versus sliding amplitude,
fretting cycles and contact area. evolution is formalized using a power law
formulation which allowed predicting wear transitions for plain and
macro-textured surfaces.
