THE STUDY ON THE TRIBOLOGICAL PROPERTIES OF PURE IRON TREATED BY IBAD

Commercial pure iron was treated by Al+N+ and Ti+N+ ion beam assisted deposition (IBAD). The authors investigated the friction and wear prop erties of samples before and after the treatment. The microstructures, composition and morphology of the wear surfaces were analyzed and the properties of the modified layers were studied. The mechanisms of the improvement of the friction and wear properties were also discussed. The experimental results indicate that the IBAD with Al+N+ or Ti+N+ ca n effectively decrease the friction coefficients and strikingly improv e the wear resistance. The compounds of Fe4N and Fe3Al formed in the s urface layers of pure iron when treated by Al+N+, while Fe2N and Fe2Ti formed when treated by Ti + N+. These compounds much strengthen the s urfaces. The IBAD treatment also promotes the formation and reform of the oxide films during the wearing process. These may transform the we ar mechanism of pure iron from adhesive wear to adhesive/oxidative wea r. (C) 1998 Elsevier Science S.A. All rights reserved.