It was previously shown that lubricating suspensions that contain Fe mesoparticles and OS 20 or ENB 904 surfactants decrease the wear of friction surfaces. However, iron particles are readily oxidized by air. Therefore, the aim of this work is to modify the surface of Fe particles with a copper shell using a transmet allization reaction for the subsequent use in tribosystems. This reaction occurs via an electrochemical mech anism. The rate of the first stage of the modification of iron with copper expressed in electrical units is close to the limiting current density of the electroreduction of Cu2 . It occurs as long as Cu2 ions are present in the solution or as long as Fe particles are not destroyed. Surfactants decrease the rate of transmetallization and can destroy iron particles. However, the modification of Fe particles directly in oil occurs at such con centrations of Cu2 that provide the modification of 10% of the particles present in the system. This method for the modification of iron has no effect on the size of the resulting particles.