Effect of Cu Content on the Structure, and Performance of Substoichiometric Cr–N Coatings

Abstract

Cu-Cr-N coatings with Cu contents between 3 and 65 at.%, Cu/Cr ratios in the 0.04-4.5 range and 21-27 at.% N, synthesized by twin electron-beam Physical Vapor Deposition at 450°C, were investigated and compared against substoichiometric Cr-N reference samples. The main objective of this study is to study the influence of Cu on the structure, and the subsequent effects on the mechanical properties, room (22°C) and high temperature (500 and 840°C) tribological performance of Cu-Cr-N coatings. Using X-ray photoelectron spectroscopy, glancing angle X-ray diffraction and scanning electron microscopy, in combination with nanoindentation mechanical property measurements and laboratory-controlled ball-ondisc sliding experiments, it is shown that Cu-Cr-N coatings with low Cu content (3 at.%) possess sufficient wear resistance for high-temperature demanding tribological applications. The lubricious effect of oxide formation at high temperatures is also evaluated.

Microstructure and properties of Cr–Cu–N coatings with ultra-low copper content

“…Baker's calculation results [11] showed that the amorphous Cu concentration required for monolayer coverage of Cr nanocrystals with the grain size of 10 nm was more than 5 at.%, and the content of Cu required got higher with decreasing nanocrystal size. But too much soft metal existed in the grain boundaries which could lead to decreased hardness [11,12].…”

Effects of Cu Addition on Microstructure and Adhesion Properties of Ti-Al-N Nanocomposite Films Deposited by Magnetron Sputtering

“…The Ti-Al-Cu-N film with Cu content of 9.44at% shows no peaks of Cu. It can be deduced that Cu phase exists either as nanocrystallines in a too low concentration for XRD detection, or as an amorphous phase, or alternatively in a dispersed form [6]. The FWHM of the (111) and (200) of the Ti-Al-Cu-N film with higher Cu content is larger than those of other films.…”

Effect of Ni content on CrNiN coatings prepared by RF magnetron sputtering

“…Baker's calculation results [35] showed amorphous Cu concentration required for monolayer coverage of Cr nanocrystals with the grain size of 10 nm was more than 5 at.%, and the content of Cu required got higher with decreasing nanocrystal size. But too much soft metal existed in the grain boundaries should lead to decreased hardness [9,[35][36]. On the basis of Baker's calculated method [37], we calculate Ni concentration required for monolayer coverage of CrN grains in Table 2.…”