High temperature gas nitridation of thermally sprayed coatings of Ti and Ti containing Ni5Al5Mo

Abstract

Titanium and a mixture of 1:1 weight ratio titanium and bond coat (Ni-5 wt.% Al-5 wt.% Mo) were thermally sprayed on mild steel disks which were subsequently nitrided in 10 cm3 s-1 ammonia at 1200 K to form titanium nitride(s). The coatings were analyzed using XRD and EDX to determine phases and elements contained in the phases. Knoop hardness (HK) values of the Ti and the mixture coatings at 25 μm depth with 1200 K nitridation are 1216.2 ± 112.5 and 1124.9 ± 221.8 kg mm-2, respectively. Pin-on-disk wear rates of the coatings with 1200 K nitridation are three orders of magnitude higher than those of the tungsten carbide pin. © 2006 Elsevier B.V. All rights reserved.