OXIDATION RESISTANCE OF Ti-6Al-4V HOT-DIPPED IN MELTED Al AND Al-12Si ALLOY

Titanium alloys have an excellent combination of mechanical strength, lightweight properties, good biocompatibility and high corrosion resistance in sea-water and oxidation medium. Of all global production of titanium, about 50% are used for production of Ti-6Al-4V, which has applications in aerospace, automotive, power generation, chemical, marine, biomedical and sports. However, the maximum work temperature for them is about 500 °C. A number of techniques of surface engineering can be used to increase the oxidation resistance of titanium and its alloys. One of those treatments that stands out is the treatment by hot-dipping in aluminum, due to the low cost and the ease and speed of the process. In this work, Ti-6Al-4V samples were subject by hot-dipping process in Al and Al-12%Si melted at 700 °C, for 2, 5, 10 and 30 minutes and isothermal diffusion treatment at 950 °C for 6 hours. The layers were characterized by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), Vickers hardness and isothermal oxidation tests in static air at 900 and 1000 °C to produce the mass gain.