Wear and corrosion resistance of a plasma-nitrided PM tool steel alloyed with niobium

摘要

The aim of this work was to evaluate the corrosion and abrasive-wear resistance of plasma-nitrided PM tool steel with increased content of niobium (2.6 wt.%). It was found that the wear behaviour was significantly influenced not only by surface hardness, but also by other factors, mainly by surface roughness and by the presence and properties of a compound layer. The maximum wear resistance was achieved by plasma nitriding at 500 degrees C for 190 min. It was also shown that nitriding led to an increase of the free corrosion potential and that the compound layer on the surface acted as a barrier against corrosion attack. The nitriding conditions that resulted in the maximum wear resistance also provided significantly increased corrosion resistance. In addition, it was observed that the conventional gas nitriding conducted at the same conditions did not produce such significant improvement of the wear resistance. (c) 2005 Elsevier B.V. All rights reserved.