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

Pigment with anticorrosive properties based on transition metal compounds

Pigments for corrosion-resisting paint and varnish materials were synthesized. Physicochemical properties (water solubility, oil-absorption power I and type II, pH of the aqueous extract) of the obtained pigments were determined. Corrosion stability of the synthesized pigments are studied by electrochemical method (in sodium chloride NaCl solutions). It is established that the pigments are cathodic corrosion inhibitors. Corrosion current density decreases by 2–3 times and protective effect of 37–68% is observed in the suspension of synthesized pigments in a solution of sodium chloride