Sintered samples containing Mo, Ni and Mn were plasma nitrided or nitrocarburized or sulphonitrocarburized with seven different cycles. After characterization the dry wear resistance of the treated samples was evaluated by an Amsler tribometer. The samples with the best wear resistance have a surface layer formed by martensite and retained austenite. A good wear resistance is also observed for the samples with a surface layer formed by a high amount of epsilon solid solution, or epsilon solid solution with a great carbon content. The samples with the worst wear resistance have the thinnest surface lavers or with the lowest amount of epsilon solid solution.