Mechanical, and Corrosion Properties of Coatings Based on ZrN Solid Solution

Abstract

The structure, elemental composition, and mechanical and corrosion properties of (Zr, Nb)N, (Zr, Hf)N and (Zr, Nb, Hf)N vacuum-arc coatings deposited on the titanium alloy Ti–6Al–4V were studied. The X-ray diffraction analysis, scanning electron microscopy, microhardness measurement, adhesion, and corrosion tests were used as investigation techniques. It was found that the coatings were single-phase solid solutions based on ZrN. The highest microhardness value (17 GPa) was observed for the (Zr, Hf, Nb)N coating, and the lowest value (9 GPa) for the (Zr, Nb)N coating. The (Zr, Hf)N coating also possessed the highest critical force Lc3 during scratch tests. Comparison with the data obtained earlier showed that a decrease of the Nb concentration in the (Zr, Nb)N coating and an increase of the Hf concentration in the (Zr, Hf)N coating led to the growth of the critical force Lc3. Corrosion tests carried out in a 3% NaCl solution in the galvanostatic mode showed that the (Zr, Nb)N coating maintained continuity over the entire surface of the alloy in contrast to the coatings containing Hf atoms.