Micro-abrasion wear testing of PVD TiN coatings on untreated and plasma nitrided AISI H 13 steel

An abrasive wear test, based on the ball-crater technique, has been used to evaluate the wear resistance of PVD TiN coatings, on untreated and plasma nitrided AISI H13 steels. Knoop microhardness measurements and scratch test s were carried out to characterise the coating systems under investigation. The TiN on plasma nitrided "duplex" coatings showed better micro-abrasive wear resistance than the single-layered TiN coatings and uncoated AISI H13 substrate. The best performance of the duplex-treated sample can be attribu ted to the presence of a nitrided subsurface in comparison with that of the single-layered TiN coating. The presence of a hard nitrided layer seemed t o diminish the scratching action of the SiC abrasive particles. The wear pa tterns also indicated a transition between wear mechanisms, depending on th e surface (coating) and subsurface hardness. A grooving wear mechanism was observed for a single-layered TiN coating (deposited on a hardened AISI H13 substrate) whilst a mixed mechanism involving grooving and rolling wear wa s found to occur in a duplex TiN coating (plasma nitrided AISI H13 substrat e). (C) 2001 Elsevier Science B.V. All rights reserved.