STRUCTURE AND PROPERTIES OF Ti-TiB COATINGS OBTAINED BY ELECTRIC SPARK TREATMENT OF Ti6Al4V TITANIUM ALLOY

Ti-TiB coatings were prepared by electric spark treatment with a non-localized electrode (NE) of a titanium substrate. Titanium granules and titanium diboride powder in various ratios were used for application. During the coating process, all samples monotonously gained weight. The average weight gain values for 10 minutes of treatment ranged from 1.6 to 3.8 mg/cm, with a minimum at sample B9 and a maximum at B6. A study of the average thickness of the coatings obtained showed comparability with the cathode gain. There are no clear boundaries and longitudinal cracks between the deposited layer and the substrate. All coatings have an inhomogeneous structure, represented by a metal matrix with dark gray inclusions, which are particles of the initial titanium diboride. The surface roughness of all prepared coatings according to the R criterion was very close and ranged from 5.13 to 9.27 microns. The average values of the microhardness of the coatings varied in the range from 13.28 to 16.81 GPa, which is 3.4 to 4.3 times higher than the uncoated titanium alloy. The cyclic heat resistance test was carried out at a temperature of 900 °C for 100 hours and showed that the final weight gain of the samples ranged from 487.0 to 583.8 g/m, which is lower than that of titanium alloy Ti6Al4V without coating (630.6 g/m) from 7 to 23%. The average values of the coatings’ wear intensity ranged from 1.26·10 to 6.3·10 mm/(N·m) at 25 N and from 0.75·10 to 3.6·10 mm/(N·m) at 70 N.