Characterization and wear properties of carbon nanotubes incorporated ceramic coatings on Ti6Al4V and Ti6Al7Nb alloys

摘要

Purpose: of this paper is characterization and wear properties of carbon nanotubes incorporated ceramic coatings on Ti6AI4V and Ti6AI7Nb alloys.Design/methodology/approach: Carbon nanotubes (CNTs) incorporated ceramic coatings were fabricated by micro arc oxidation (MAO) method to improve the tribological performance of Ti6AI4V and Ti6AI7Nb alloys for wear resistant applications. Titania and CNTs incorporated titania coatings were formed on Ti6AI4V and Ti6AI7Nb alloys via MAO process. Surface and cross-sectional morphology, phase composition, thickness and roughness of the ceramic coatings were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and surface profilometer.Findings: Wear behavior of bare titanium alloys and those of their oxidized surfaces (with and without CNTs addition) were evaluated by reciprocating wear test against 100Cr6 steel ball at dry sliding condition. XRD analyses of the oxidized samples demonstrated that coatings were consisted mainly of rutile and aluminum titanate. Surface morphologies of the coatings revealed that CNTs addition into the electrolyte led to generation of less porous, flat regions surrounded by relatively irregular-shaped pores on the surface of the coatings. Wear rate of CNTs incorporated coatings was decreased significantly compared to coatings generated without CNTs addition.Research limitations/implications: CNTs addition into the base electrolyte sharply decreases wear rate of both alloys, and there is no significant difference between the wear rates of Ti6AI4V and Ti6AI7Nb alloys oxidized in CNTs added electrolyte.Originality/value: Titanium and its alloys are attracting a great deal of attention especiallyin automotive and aerospace industries. However, titanium-based materials tend to haveinsufficient wear resistance in abrasive conditions. In an attempt to overcome this limitation,carbon nanotubes (CNTs) incorporated ceramic coatings were fabricated.