Effect of Sb and Sn on the corrosion behavior of low alloy steel in simulated polluted marine atmosphere

The influence of Sn and Sb on the corrosion resistance of low-alloy steel in a simulated polluted marine atmosphere was explored to accumulate corrosion data for the design, development and use of high-performance low-alloy steel in China. Sn and Sb micro alloyed low-alloy steels were prepared through vacuum smelting, and the corrosive behavior of low-alloy steels in simulated polluted marine atmosphere was studied using accelerated immersion tests. The results showed that the five low-alloy steels are all bainite, Sn and Sb are distributed in the low-alloy steel in the form of solid solution. Adding Sn and Sb can slow down the corrosion rate of low-alloy steel in simulated polluted marine atmosphere. Sn-containing steel has larger corrosion pits in the early stage of corrosion, and the development speed slows down in the later stage of corrosion. Adding Sn can generate SnO2 in the rust layer, promote the transformation of γ-FeOOH to α-FeOOH in the rust layer, and improve the compactness of the rust layer. The development speed of corrosion pits of Sb-containing steel is always slower than that of BS low alloy steel. Sb can generate a stable product, Sb₂O₃ in the rust layer, promote the transformation of γ-FeOOH into Fe₃O₄ in the rust layer, and improve the stability of the rust layer. The addition of Sn and Sb has no effect on the microstructure of low alloy steel. The addition of Sn and Sb can improve the stability and compactness of the rust layer by improving the phase composition of the rust layer, and prevent corrosive ions from entering the surface of the steel substrate, thereby improving the corrosion resistance of low-alloy steel in a simulated polluted marine atmosphere.