抑制劑對被覆鋼材在土壤之模擬環境中之腐蝕行為影響

The Influence of Inhibitor on the Corrosion Behavior of Coated Steel in Simulated Soil Environments

本研究旨在探討API 5L-B鋼材在模擬土壤環境的水溶液（0.1 M NaCl + 0.1 M Na2SO4）中的腐蝕現象，腐蝕抑制劑的添加以及防蝕被覆層破損時對鋼材腐蝕的影響是主要研究重點。交流阻抗測試結果顯示，在pH 7的模擬環境中，添加0.01 M的Na2MoO4可以增加鋼材的電荷轉移電阻。浸漬試驗結果顯示鋼材在模擬被覆破損情況下，被覆層的去層化會使腐蝕沿著被覆材／底材界面往內擴展。試片在經過預浸在含抑制劑之水溶液以後，在pH 7的模擬環境中，浸漬試驗結果顯示，被覆層去層化的現象獲得改善。

The purpose of this study is to investigate the corrosion behavior Of API 5L-B steel in a simulated soil environment (0.1 M NaCl + 0.1 M NaSO4). The effects of corrosion inhibitors (Na2MoO4 and Hexamine) and coating defects on the corrosion behavior of API 5L-B steel are also studied. The electrochemical impedance spectroscopy (EIS) revealed that the addition of 0.01 M Na2MoO4 leads to an increase of Rct of the steel. The results from immersion tests of coated steels containing coating defects showed that delimination of coating caused corrosion to extend between coating/substrate interface. Furthermore, the extend of the undercoating corrosion become less severe for the specimens pre-immersed in inhibitor solutions before immersion test in simulated soil environments of pH 7.