Microstructure, Mechanical and Tribological Properties of Advanced Layered WN/MeN (Me = Zr, Cr, Mo, Nb) Nanocomposite Coatings

Abstract

Due to the increased demands for drilling and cutting tools working at extreme machining conditions, protective coatings are extensively utilized to prolong the tool life and eliminate the need for lubricants. The present work reports on the effect of a second MeN (Me = Zr, Cr, Mo, Nb) layer in WN-based nanocomposite multilayers on microstructure, phase composition, and mechanical and tribological properties. The WN/MoN multilayers have not been studied yet, and cathodic-arc physical vapor deposition (CA-PVD) has been used to fabricate studied coating systems for the first time. Moreover, first-principles calculations were performed to gain more insight into the properties of deposited multilayers. Two types of coating microstructure with different kinds of lattices were observed: (i) face-centered cubic (fcc) on fcc-W2N (WN/CrN and WN/ZrN) and (ii) a combination of hexagonal and fcc on fcc-W2N (WN/MoN and WN/NbN). Among the four studied systems, the WN/NbN had superior properties: the lowest specific wear rate (1.7 × 10−6 mm3/Nm) and high hardness (36 GPa) and plasticity index H/E (0.93). Low surface roughness, high elastic strain to failure, Nb2O5 and WO3 tribofilms forming during sliding, ductile behavior of NbN, and nanocomposite structure contributed to high tribological performance. The results indicated the suitability of WN/NbN as a protective coating operating in challenging conditions.

Microstructure, Mechanical and Tribological Properties of Arc Ion Plating NbN-Based Nanocomposite Films

“…It is demonstrated that the as-deposited films have many surface defects, namely droplets, particles and craters, which are mainly caused by liquid droplets emitted from the surface of the Nb and Ag targets during film deposition process. The defect density on the surface of NbN-Ag and NbN/NbN-Ag films is higher than that of NbN film, which is due to the lower melting point of Ag (962 °C) than Nb (2468 °C), and hence the Ag droplets are formed more easily [ 27 ]. As can be seen from the insets of Figure 1 b, the large Ag droplets and a relatively small Nb droplet are distributed on the Ag-doped film surface.…”

The influence of multilayer architecture on the structure and mechanical properties of WNx/TiSiN coatings in comparison with WNx and TiSiN single layers

“…The multilayer is composed of the alternating layers of darker TiSiN and brighter WN x . In backscatter electron imaging, heavier elements can backscatter primary electrons stronger than light elements [25,26]. Hence, heavier elements appear brighter.…”

Composite Materials with Nanoscale Multilayer Architecture Based on Cathodic-Arc Evaporated WN/NbN Coatings

“…Furthermore, as can be seen, magnetron sputtering is the predominant deposition technique. In our previous study, we successfully synthesized WN/ZrN, WN/CrN, WN/MoN, and WN/NbN coatings under the same deposition conditions using the CA-PVD method and comprehensively characterized them . This approach aimed to elucidate the system that exhibited the best tribomechanical properties.…”