Wear 271 (2011) 2116–2124 Contents lists available at ScienceDirect Wear j o ur nal ho me p age: www.elsevier.com/locate/wear A study of the wear performance of TiN, CrN and WC/C coatings on different steel substrates E.E. Vera a , M. Vite b , R. Lewis c , E.A. Gallardo b , J.R. Laguna-Camacho d,∗ a Universidad Politécnica de Pachuca, Zempoala Hgo., Mexico b Department of Mechanical Engineering, Tribology Group, SEPI-ESIME-IPN, UZ Edificio 5, Tercer piso, Av. IPN S/N, Col.Lindavista, C.P. 07738, México City, D.F., Mexico c University of Sheffield, Department of Mechanical Engineering, Mappin Street, Sheffield S13JD, United Kingdom d Universidad Veracruzana, Faculty of Electric and Mechanical Engineering, Av. Venustiano Carranza S/N, Col. Revolución, C.P. 93390, Poza Rica, Veracruz, Mexico a r t i c l e i n f o Article history: Received 30 August 2010 Received in revised form 7 December 2010 Accepted 9 December 2010 Keywords: Film coating thickness Sliding wear Optical microscopy Energy dispersive X-ray a b s t r a c t In this study, the performance of the coatings TiN, CrN and WC/C applied on steel substrates that were subjected to sliding wear was analyzed. These materials normally exhibit an efficient performance in applications such as coatings of cutting tools, stamping processes, forming and plastic injection tooling where the contact and sliding conditions are severe. Due to this fact, this research was conducted to characterize the materials in relation to the wear process. The sliding wear test was performed using a reciprocating wear test machine. All tests were conducted in dry conditions with a room temperature between 20 ◦ C and 23 ◦ C and 45% to 50% relative humidity. A sliding velocity of 0.08 m/s and 2 mm ampli- tude were used. The applied loads were 11.76 N (Po = 1.74 GPa) and 7.84 N (1.52 GPa), respectively. Optical microscopy and scanning electron microscopy (SEM) were used to observe and analyze the wear mech- anisms. Additionally, the variation of the friction coefficient versus the number of cycles was obtained. This was used to determine with a higher precision the time (presented as number of cycles) where the coating presented the initial signs of wear damage. In addition, energy dispersive X-ray analysis (EDS) was performed to obtain the chemical composition of the materials and hardness tests on the wear tracks were also carried out. It was possible to know the wear life of these coatings and possible causes of life variations. The load was an important factor in the variation of the wear life results, although other factors such as surface roughness and coating thickness were also significant. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Ceramic coatings have been proven to be a good candidate for protecting the base material against wear, corrosion, erosion and other un-expected damage. In the field of thin solid films (< 10 m), titanium nitride (TiN) is still the most widely accepted in engi- neering applications. This coating can be produced either by the physical vapour deposition (PVD) or chemical vapour deposition (CVD) method. The combination of high hardness, wear resistance, chemical inertness and low friction coefficient characteristics in TiN makes it attractive as a tribological coating. It is generally used in the fields of forming, drawing and cutting tools, moulds, components and decorations, gear and bearing applications [1,2]. Several research works have provided useful information for prac- tical applications. For instance, J.A. Sue and H.H. Troue [3] carried out a study of the friction and wear properties of titanium nitride coating in sliding contact with AISI 01 steel. Reciprocating sliding tests were ∗ Corresponding author. Tel.: +52 782 82 38143. E-mail address: juanrlaguna@hotmail.com (J.R. Laguna-Camacho). conducted using a block-on-ring wear test machine. The results showed that wear occurs mainly in the 01 steel block and much less wear was found in the TiN coating ring. Additionally, the wear mechanisms were identified to be an adhesive transfer of wear frag- ments produced in the start by the removal of 01 steel and TiN asperities by abrasive wear between the two contacting surfaces. Three body abrasive wear was observed to occur due to the contact between the two surfaces but also by the transferred layer trapped between them. Plastic deformation and oxidative wear were other wear mechanisms identified. Chrome nitride (CrN) is typically known by a relatively low friction coefficient, high hardness, high toughness, good wear resis- tance and a high corrosion resistance under extreme temperature conditions. This is used as a coating in cutting, milling and screw- threading tools, injection components, extrusion dies, punches, pump parts, shafts and in forming industries [4]. Some researchers have shown that the wear behaviour of CrN is better than that of TiN [5]. In addition, CrN can be deposited much more thickly than TiN which has served as motivation to conduct research works on this coating as a possible candidate to prevent the base material from the wear damage [6]. 0043-1648/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.wear.2010.12.061