Effect of active screen plasma nitriding pretreatment on wear behavior of TiN coating deposited by PACVD technique

Titanium based alloys are used extensively for improving wear properties of different parts due to their high hardness contents. Titanium nitride (TiN) is among these coatings which can be deposited on surface using various techniques such as CVD, PVD and PACVD. Their weak interface with substrate is one major drawback which can increase the total wear in spite of favorite wear behavior of TiN. Disc shaped samples from AISI H13 (DIN 1.2344) steel were prepared in this study. Single TiN coating was deposited on some of them while others have experienced a TiN deposition by active screen plasma nitriding (ASPN). Hardness at the surface and depth of samples was measured through Vickers micro hardness test which revealed 1810 Hv hardness as the maximum values for a dual-layered ASPN-TiN. Pin-on-disc wear test was done in order to study the wear mechanism. In this regard, the wear behavior of samples was investigated against pins from 100Cr6 (Din 1.3505) bearing steel and tungsten carbide-cobalt (WC-Co) steel. It was evidenced that the dual-layer ASPN-TiN coating has shown the least weight loss with the best wearing behavior because of its high hardness values, stable interface and acceptable resistance against peeling during wearing period.

► Disc shaped samples were prepared from AISI H13 (DIN 1.2344) steel. ► Samples were exposed to active screen plasma nitriding (ASPN). ► TiN layer was deposited on all samples through PACVD technique. ► ASPN pretreatment prevents a very hard layer of 1810 Hv on a not so hard substrate. ► Weight loss of samples which had experienced ASPN pretreatment was very low.