Comparison of the Mechanical Properties and Corrosion Resistance of the Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN Coatings

In this work, the mechanical properties and corrosion resistance of Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN coatings deposited by the physical vapor deposition (PVD) method on Ti-6Al-4V alloy were compared. The phase composition of the coatings, their hardness and fracture resistance in scratch tests were determined, and their structural characteristics were also studied using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The diffraction spectra were made using an automatic X-ray diffractometer. The value of the adhesive component of the friction coefficient f adh of the pair “coated and uncoated Ti-6Al-4V alloy” was investigated in the temperature range of 20–900°C. The lowest value of f adh was detected for the Zr-ZrN coating at temperatures below 400°C, while for the Mo-MoN coating it was observed at temperatures above 700°C. The polarization curves of the coated and uncoated samples were performed in a 3% aqueous NaCl solution. The level of corrosion of the Ti-6Al-4V alloy samples with Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN coatings was evaluated using the Tafel extrapolation method, the iteration method, and the polarization resistance method. The results obtained with these methods indicate that the Zr-ZrN coated sample has the best corrosion resistance in the 3 wt.% NaCl solution, with a corrosion current density of 0.123 µA/cm 2

Effect of adhesion and tribological properties of modified composite nano-structured multi-layer nitride coatings on WC-Co tools life

The paper presents the results of the comparative tests of carbide samples with multilayered nano-structured coatings based on titanium nitrides (Ti-TiN-(Ti,Cr,Al,Si)N) and zirconium nitrides (Zr-ZrN-(Nb,Zr,Cr,Al)N and Zr-ZrN-(Zr,Al,Si)N). The phase composition and microstructure of these coatings were studied. The scratch test method was applied to study the adhesion bond strength to the substrate and the coating fracture patterns. The tribological parameters of the coated samples were studied at temperatures of 450°C-900 °C. The cutting properties of the tools with the coatings under study were investigated in turning AISI 321 steel. Various coating parameter effects on the cutting tool life were studied