Effect of 0.3 wt.% Al Addition in Flowing Liquid Zinc on the Erosion-Corrosion Behavior of Fe-3.5 wt.% B Alloy

The effects of 0.3 wt.% Al added to flowing liquid zinc on the corrosion inhibition and erosion-corrosion interfacial characteristics of Fe-3.5 wt.% B alloy were investigated in order to separate the pure erosion rate from the total erosion-corrosion rate and further study the erosion-corrosion interaction created by flowing zinc. The result indicated that the erosion-corrosion rate increased slowly and then sharply thereafter, while the corrosion-inhibition rate increased linearly and slowly at a bath temperature of 460-550 °C. The corrosion-inhibition efficiency of 0.3 wt.% Al addition in the flowing liquid zinc bath was significantly reduced and then enhanced with increasing bath temperatures, depending on the interfacial microstructures after Al-corrosion inhibition. A uniform and continuous Fe₂Al₅Zn_x inhibition layer, which suppressed the corrosion reaction of iron and zinc, formed on the erosion-corrosion interface of the Fe-3.5 wt.% B alloy, thereby reducing the spallation of anticaustic Fe₂B skeleton. Moreover, the gradual deterioration of the inhibition layer led to a reduction in the corrosion-inhibition ability. The present results indicate that, due to the beneficial Al-corrosion inhibition effect, the corrosion-inhibition rate as the pure erosion rate of Fe-3.5 wt.% B in flowing liquid zinc can be well separated from the erosion-corrosion rate by adding 0.3 wt.% Al to flowing liquid zinc bath.