Role of Iron in the Amorphization Process in Friction-Induced Phosphate Glasses

Wear debris from ZDDP lubricated tests run under mild wear conditions have been investigated by X-ray Absorption Fine Structure Spectroscopy (EXAFS). Special attention has been paid to the state of iron in the amorphous wear fragments. Results indicate the presence of Fe3+ species as a modifier of the phosphate network formed during tribo-reaction. As the anti-wear regime of ZDDP is characterized by a decrease of the abrasive wear, it is suggested that the anti-wear action of ZDDP is reliable to the diffusion of iron oxides in the phosphate, this latter being gently delaminated. Presented at the 43rd Annual Meeting in Cleveland, Ohio May 9–12, 1988