Microstructure and mechanical properties of Cr–Ni–N coatings deposited by HiPIMS

Abstract

Cr-Ni-N coatings, the Ni content of which was altered from 0 to 6?3 at-%, were deposited by a hybrid coating system consisting of high power impulse magnetron sputtering and radio frequency magnetron sputtering. The effects of Ni addition to Cr-N coatings on the microstructure and mechanical properties of the coatings were investigated in this study. The instrumental analysis revealed that the Ni element was incorporated into Cr-N crystals as solid solutions, while excess Ni was precipitated as nanocrystalline phases at the Cr-N grain boundaries. The toughness of the Cr-Ni-N coatings was significantly improved with Ni content increased. In addition, the hardness of the coatings slightly increased from 30?4 to 32?6 GPa due to the grain refinement effect and solid solution hardening. From the tribological tests, the highest wear resistance was obtained from the sample having a Ni content of 2?7 at-%.

Structural and mechanical properties of Cr–Zr–N coatings with different Zr content

“…These results reveal that the N content slightly decreased with increasing Zr, which led to an understoichiometric case of Cr-Zr-N coatings (N/(Cr +Zr)∼0.94) and an increase in Zr/Cr ratio from 0 to 4.26 with increasing the applied power of Zr target. The oxygen contamination in all the coatings was found to be very low in the range of 2-3.8 at.-%, which is interstitially induced in the films [3,10,14]. Figure 1 shows the XRD patterns of the Cr-Zr-N coating with varying Zr content, deposited onto XC100 steel substrates.…”

“…However, at 29 at.-% of Zr ( Figure 6(c)), an adhesive critical high load (Lc 2 ≈ 34.3 N) and delamination fracture mechanism of coating from the substrate was observed at the edges of the scratches track. This was mainly due to the adhesive action of the wear debris [3,10,11].…”

Effect of Zr content on friction and wear behavior of Cr‐Zr‐N coating system

“…This shows that Zr containing films exhibit a higher covalence level than pure CrN, which could account for the hardness increase. 18,51 The residual stress followed the same pattern as that of hardness, 52 which showed a small increase from -1.86 GPa to -2.1 GPa at 7.1 and 31.8 at.% Zr, respectively (Figure 6). This pattern is suggestively caused by the incorporation of Zr atoms into the interstitial nitrogen sites.…”

“…According to XPS analysis, the peak shifts in Cr 2p binding energy suggest that the bonding character changed from the Cr‐N to the Cr‐Cr bonds due to the charge transfer from nitrogen to Cr atoms as a function of Zr content. This shows that Zr containing films exhibit a higher covalence level than pure CrN, which could account for the hardness increase …”

Effects of Negative Bias Voltage and Ratio of Nitrogen and Argon on the Structure and Properties of NbN Coatings Deposited by HiPIMS Deposition System

“…In those methods, however, sputtering deposition is still widely used at current due to its advantage such as low cost, easy to control deposition process, and smooth surface of coatings without droplets. As a newly developed physical vapor deposition (PVD) sputtering technique, the HiPIMS has many merits to obtain coatings such as good adhesion with substrates, dense structure and optimized tribological properties, even when using low deposition temperature and low bias voltage compare to conventional sputtering and arc ion plating deposition [16,17]. In the works by Giudice et al and Paulitsch et al [18,19], the obtained coatings (Nb/TiN and Cr/TiN) deposited by HiPIMS had higher hardness, more uniform and denser structure coatings than DC magnetron sputtering.…”