Sliding wear behavior of duplex coatings with different plasma nitride layers and a Cr‐Al‐Ti‐B‐N coating

Abstract

The dry sliding wear behavior of AISI D2 tool steel is investigated under different heat treatment states in hardened, plasma nitrided, and duplex layer conditions. Plasma nitriding (PN) is performed at 510-520 • C with varying N 2 -H 2 gas mixtures, and Cr-Al-Ti-B-N layers are deposited at 480 • C by means of physical vapor deposition (PVD). This work investigates the influence of the nitride layer and, in particular, the presence of a compound layer on the tribological behavior of the duplex layer system. Therefore, as-nitrided conditions both without and with a compound layer -as well as with a mechanically removed compound layer -are subsequently hard coated. Comparative ball-on-disc wear tests in linear-reciprocating sliding motion against WC-Co counterbody balls are conducted at a load of 120 N. Compared to sample states without a compound layer, the as-nitrided states with a compound layer exhibit improved wear coefficients. In contrast, all duplex layer states exhibit comparably low friction coefficients and low wear coefficients independently of the presence of a compound layer.Removal of the compound layer prior to PVD coating leads to a significant reduction in wear resistance due to reduced surface roughness before the hard coating and the associated change in the bonding between the nitride layer and hard coating. K E Y W O R D Scompound layer, duplex surface engineering, friction and wear, plasma nitriding, PVD hard coating INTRODUCTIONTool steels are the preferred materials for most fields of application with demanding tribological working conditions -such as die casting, forging, stamping, cutting, and rolling. [1][2][3] One widely used representative of this group of steels is X155CrVMo12-1 (AISI D2), which is applied in complex applications involving, for example, high normal loads and sliding speeds. 4,5 In order to counteract the associated reduction in tool life, hard coatings produced by surface treatment techniques such as plasma nitriding (PN) and physical vapor deposition (PVD) hard coating are commonly applied. PN affords significant improvements in surface hardness, fatigue strength, corrosion, and wear resistance 3,4,6 compared to conventional steels. However, nitrided layers do not provide sufficient resistance in highly aggressive environments or under heavy mechanical stresses. [2][3][4]6,7 PVD hard coatings are mainly used because of their high hardness and excellentThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Duplex Treatment of AISI 420 Steel by RF-ICP Nitriding and CrAlN Coating Deposition: The Role of Nitriding Duration

“…This also works for the samples with a low thicknesses of CL (1.3 µm) and DZ (5.3 µm) after 10 min nitriding using the RF-ICP source. It is well known that the duplex treatment can lead to increased coating adhesion on the hardening substrate due to the enhanced load-bearing capacity of the nitrided substrate [8,12,14]. The same dependence was found in the present study.…”

“…Thicker nitriding of the steel substrate should be performed to improve coating adhesion. Moreover, the increased surface roughness (R a ~0.03→0.21 µm) can also result in better coating adhesion parameters because of a penetration of coating atoms in the surface grooves and pores of the nitrided steel, leading to enhanced bonding of the coating in comparison with deposition onto a polished surface [12,44]. Nevertheless, as the CL composed of the ε-Fe 2-3 N phase forms on the outer surface, the coating adhesion will be decreased.…”

“…To reduce the difference in mechanical properties between hard coatings and substrate material, substrate hardening by plasma nitriding (PN) is in high demand. The combination of PN and coating deposition can be used in one technological process, known as duplex treatment [9][10][11][12][13][14].…”

Nitriding Effect on the Tribological Performance of CrN-, AlTiN-, and CrN/AlTiN-Coated DIN 1.2367 Hot Work Tool Steel

“…Interfacial adhesion can be significantly improved by changing the mechanical parameters of the material surface before coating deposition is performed [ 7 ] by nitriding or heat treatment of the surface [ 8 ]. The combination of nitriding and subsequent coating is called duplex surface treatment technology, which can be used for different applications depending on the specific requirements [ 9 , 10 ].…”

Effects of TiN/CrN, CrAlN, and TiN Coatings on the Performance of AISI M2 Tool Steel

“…If the punch surface contacting the formed part wears and the amount of wear rises, the hole diameter of the part may alter and become dimensionally unstable, as well as the surface of the hole being of poor quality, which may result in higher manufacturing costs. Surface quality (performance) of forming tools, such as enhanced wear resistance, can be improved by utilizing various surface treatments [7][8][9][10][11]: plasma vapour deposition (PVD), chemical vapour deposition (CVD), plasma immersion ion implantation, and plasma electrolyte nitriding.…”