Direct chemical vapor deposition of diamond on Fe-15%Cr steels modified by 5%Si, 5%Al, 5%Ti, 10%Mo and 10%Mn, 20%Cr (in wt.%), respectively, has been performed at 670 degrees C with a microwave plasma reactor. Only aluminum facilitates form dense, continuous and adherent diamond films with a maximum thickness of 3 mu m, while diamond films grown on the rest substrates spontaneously delaminate after cooling down. (c) 2007 Elsevier B.V. All rights reserved.