The coated layers fabricated on the tool steel D2 by thermoreactive deposition/diffusion (TRD) and TRD + plasma nitriding have been investigated on the tribologic characteristics against the counter ring made of a hardened 02 steel. The test was conducted in a block-on-ring tribometer in dry wear condition in the air. The results showed that the chromium carbide, Cr7C3-dominated layer, provided by the TRD performed poor wear resistance even worse than that of the neutral hardened D2 steel because of tribochemical reaction and microploughing. However, the chromium nitride, CrN, layer derived from the post-treatment of plasma nitriding exhibited an outstanding wear resistance due to abrasion action. (C) 2004 Elsevier B.V. All rights reserved.