Isothermal corrosion TiAl–Nb alloy in liquid zinc

The isothermal static corrosion of TiAl–Nb alloy compared with the WC–Co coating in liquid zinc at 450 °C was studied. The results showed that the alloy exhibited much higher liquid zinc corrosion resistance than the WC–Co coating. The high corrosion resistance of the alloy was mainly attributed to the oxide layer caused during electrical discharge machining (EDM). The oxide layer was consisted of a mixture of alumina and titania which was quite inert with respect to zinc. The corrosion of the alloy in liquid zinc was controlled by the dissolution mechanism and caused by a localized breakdown in the oxide layer. The alloy seemed to have very high potential for use in the bath hardware application of the hot-dip galvanizing industry. The alloy should be further investigated as liquid zinc corrosion resistant coating. The effect of the oxide layer, residual stress and surface roughness caused by EDM on the liquid zinc corrosion resistance of the alloy was discussed.