Effect of hot-dip aluminizing on the oxidation resistance of Ti–6Al–4V alloy at high temperatures

Hot-dip aluminizing and interdiffusion treatment were used to develop a TiAl3-rich coating on Ti–6Al–4V alloy. Interrupted oxidation at temperatures from 600 to 900 °C and isothermal oxidation at 700 and 800 °C of the coating were conducted. The coating markedly decreases the oxidation rate in comparison with the alloy at temperatures below 800 °C during the interrupted oxidation. The oxidation kinetics follows parabolic relations at 700 and 800 °C during the isothermal oxidation. A layered structure of Al2O3/TiAl3/TiAl2/TiAl/alloy from the outside to the inside forms after oxidation at 700 °C without changing the main body of the coating.

► A TiAl3 coating has been developed on Ti–6Al–4V by hot-dip aluminizing.
► The coating provides a high degree of protection for Ti–6Al–4V at 700 °C.
► A layered structure of Al2O3/TiAl3/TiAl2/TiAl/alloy forms at 700 °C.
► A layered structure of Al2O3/(TiAl3 + TiAl2)/TiAl/Ti3Al/alloy forms at 800 °C.