Wear and Corrosion Properties of Laser-Cladding Ti-Hf-Mo-Ta-Nb-B Coating on Ti60 Titanium Alloy

Ti60 is a type of high-temperature titanium alloy that not only withstands high temperatures during long-term service, but also has excellent wear resistance and corrosion resistance. To enhance the wear and corrosion resistance of a Ti60 substrate, a Ti-Hf-Mo-Ta-Nb-B coating was fabricated onto a Ti60 substrate by the laser-cladding method. Based on the principle of the pin-on-disk friction-wear test and using an electrochemical workstation platform, the wear resistance and corrosion resistance of both the laser-clad coating and the Ti60 substrate were tested, respectively. The results show that the wear resistance of the coating is significantly improved compared to the Ti60 substrate, with the wear rate being only one-tenth of that of the substrate. Among them, the wear rate of the former is 6.28 × 10−4 mm3/(N·m), while that of the latter is 6.57 × 10−3 mm3/(N·m). Additionally, the corrosion resistance of the coating in 3.5 wt.% NaCl solution is superior to that of the as-received Ti60 substrate, exhibiting a higher corrosion potential (Ecorr) of −0.3275 V and a lower corrosion current density (icorr) of 4.1801 × 10−6 A·cm−2, compared to the substrate’s values of −0.4516 V and 7.4039 × 10−6 A·cm−2, respectively. The enhanced wear and corrosion resistance of the coating is primarily attributed to the formation of a hard and corrosion-resistant high-entropy diboride phase (Ti0.2Hf0.2Mo0.2Ta0.2Nb0.2)B2.