Deposition of Ti–Ni–Zr–Mo–Al–C Composite Coatings on the Ti6Al4V Alloy by Electrospark Alloying in a Granule Medium

Abstract

The paper describes deposition of Ti–Ni–Zr–Mo–Al–C composite coatings on the Ti6Al4V alloy by electrospark alloying in a medium consisting of granules of individual metals and a Ti₃Al + 10%C alloy. The mass transfer pattern during deposition is studied; it is found that the mass transfer coefficient is 18%. The thickness of the deposited coatings is about 50 μm. According to X-ray diffraction analysis, the coating composition is represented by AlNi₂Ti, MoNi₄, and NiTi intermetallic compounds. The average roughness of the coatings R_a is about 3 μm. The microhardness of the deposited layer is three times higher than that of the Ti6Al4V titanium alloy. The wear resistance of the Ti–Ni–Zr–Mo–Al–C coating to dry sliding friction against steel R6M5 is five times higher than that of the Ti6Al4V alloy. The presence of a Ti–Ni–Zr–Mo–Al–C coating on the Ti6Al4V alloy leads to a twofold increase in the surface resistance to high-temperature gas corrosion. The proposed approach makes it possible to obtain electrospark composite coatings based on multicomponent alloys, which are not inferior to coatings prepared by conventional electrospark alloying, in an automatic mode without sophisticated hardware and software.