磷酸盐缓蚀溶液中铜离子对碳钢腐蚀行为影响

Effect of Copper Ions on Corrosion Behavior of Carbon Steel in Phosphate Corrosion Inhibition Solution

采用质量法、扫描电子显微镜以及能谱法研究碳钢在含铜磷酸盐溶液中的腐蚀性能。在含有不同浓度铜离子的磷酸盐溶液中,20~#钢的质量变化大于Q235B和20G钢。当铜离子浓度增加到1mg/L、2mg/L时,20~#表面产生了宏观腐蚀坑,表面发现大量铜析出,腐蚀主要控制形式由均匀腐蚀转向了局部腐蚀。在含1mg/L、2mg/L铜离子的磷酸盐溶液中,磷酸盐浓度由150mg/L增加到300mg/L时,20~#钢表面无宏观腐蚀坑,表面存在少量铜析出;增加磷酸盐浓度可以在一定程度上抑制铜在表面的析出,抑制局部腐蚀发生。

The corrosion behaviour of carbon steel in phosphate inhibitor containing copper ions was investigated by gravimetric method,scanning electron microscope,and energy dispersive spectrometer.The weight loss of 20#steel is larger than that of Q235B steel and 20G steel immersed in phosphate inhibitor containing copper ions.Macro corrosion pits are observed on the surface of 20#,when the contents of copper ions increased to 1 mg/L and 2mg/L.Meanwhile,a little bit of copper precipitation is detected on the surface of carbon steel,and the main corrosion type is transformed from general corrosion to localized corrosion.No obvious macro pits and only negligible copper precipitation are observed on the surface of 20#steel when the content of phosphate increases from 150mg/L to 300mg/L containing 1mg/L and 2mg/L copper ions.It means that the increase of phosphate can depress the precipitation of copper and localized corrosion.