Synergistic Effect of NaCl and SO₂ on the Initial Atmospheric Corrosion of Zinc Under Wet–Dry Cyclic Conditions

Qi Yin^1,2，Zhen-Yao Wang¹，Miao-Ran Liu^1,3，Chen Pan¹

1. Environmental Corrosion Center, Institute of Metal Research,Chinese Academy of Sciences2. School of Materials Science and Engineering,University of Science and Technology of China3. University of Chinese Academy of Sciences

摘 要：The synergistic eff ect of NaCl and SO₂ on the atmospheric corrosion of zinc has been studied at equivalent total but different ratios of molar deposition rate under wet–dry cyclic conditions. The results show that the corrosion rates, corrosion morphologies and the composition of the corrosion products are strongly infl uenced by the molar deposition rate ratio of NaCl and SO₂（NaCl/SO₂）. The corrosivity of NaCl and SO₂ toward zinc increases in order of SO₂ < 1:3 < 3:1 < NaCl < 1:1. The corrosion morphology is patchy corrosion for Group 1:1, while it is pocking corrosion for the other four experimental groups. The corrosion product containing sulfur and chlorine detected on zinc is Gordaite（NaZn₄SO₄（OH）₆Cl·6H₂O）, which has quite porous structure and was supposed to cause the patchy corrosion tendency of zinc in Group 1:1. In addition, soluble zinc corrosion products, which can inhibit the atmospheric corrosion process of zinc, were found on zinc samples in Groups 1:3 and SO₂ and connected to the lower corrosion rates of zinc in these two groups.

关键词：