A technique has been proposed for deposition of Nb–Ti coatings on titanium alloy Ti6Al4V by electric spark treatment in a mixture of titanium granules with the addition of niobium powder from 2 to 6 об.%. The results of the structure study of the obtained coatings by metallography, X-ray analysis and scanning electron microscopy are presented. It was shown that the thickness of the coatings was in the range from 31.8 to 35.9 microns. The structure of the coatings is represented by the β-phase of an Nb–Ti alloy with a niobium concentration from 44.6 to 49.1 at. %. The corrosion properties of the coatings were studied by potentiodynamic polarization and electrochemical impedance spectroscopy in a 3.5% NaCl solution, and a study of the cyclic oxidation resistance of samples was carried out at a temperature of 900°C for 100 hours. It was shown that Nb–Ti coatings, contrary to literature data, did not improve the anti-corrosion properties of the Ti6Al4V alloy. The microhardness of the coatings was studied under a load of 0.5 N, and the tribological properties in dry sliding mode under a load of 25 N. It was shown that the hardness of the prepared Nb–Ti coatings was 4.9–4.95 GPa, and the friction coefficient was in the range from 0.88 to 0.74. The deposition of electrospark Nb–Ti coatings using the proposed method makes it possible to increase the wear resistance of the surface of titanium alloy Ti6Al4V up to 11 times.
Burkov et al. (Wed,) studied this question.