Effect of Cl-/SO2-4 mass ratio on corrosion behavior of zinc-coated steel and stainless steel in dark brown forest soil
[Introduction]The effects of chloride ions(Cl-)and sulfate ions(SO24-)on the corrosion of typical grounding materials in dark brown forest soil in Jilin need to be studied.[Method]The corrosion rates of zinc-coated steel and 304 stainless steel at different Cl-/SO24-mass ratios were examined by indoor accelerated corrosion test.The changes of corrosion products of zinc-coated steel and 304 stainless steel were analyzed by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The corrosion mechanisms of zinc-coated steel and 304 stainless steel were discussed.[Result]The presence of low concentration of SO24-promoted the pitting corrosion of zinc-coated steel caused by Cl-,while high concentration of SO24-slowed down the pitting corrosion of zinc-coated steel.However,the zinc coating whose thickness was limited would gradually lose its anticorrosive effect due to rapid dissolution in strongly acidic environment.Compared to zinc-coated steel,304 stainless steel had better corrosion resistance in dark brown forest soil,but its cost was higher.In addition,the pitting corrosion of 304 stainless steel became worse with the increasing of Cl-/SO24-mass ratio.[Conclusion]Zinc-coated steel is applicable to mild neutral soil condition.304 stainless steel is not suitable for soil environments with high concentration of corrosive anions though it has better corrosion resistance than zinc-coated steel.
zinc-coated steelstainless steelsoil corrosionchloride ionsulfate ion
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