碳鋼在含六次甲基四胺酸洗液中之腐蝕特性研究

The Corrosion Behaviors of Mild Steel with Hexamethylenetetramine Inhibitor in Pickling Process

酸洗腐蝕抑制劑可藉由在金屬表面形成吸附層以阻止氫離子之放電或金屬離子之溶解。碳鋼（mild steel, MS）在酸洗製程中常使用含氮之抑制劑作為腐蝕抑制劑。在本研究中藉由重量損失的測試，探討酸洗溫度、酸洗時間等參數的變化，對碳鋼材料在酸洗製程中添加六次甲基四胺（hexamethylenetetramine, HMTA）抑制劑時，其腐蝕抑制效率與其他腐蝕特性之影響。由實驗結果顯示，腐蝕抑制效率隨時間之增加而增加，腐蝕抑制效率由室溫至40℃亦隨之增加。在較高溫度（80℃）時，腐蝕抑制效率較低溫為高且幾乎與酸洗時間無關。在鹽酸酸洗液中添加HMTA抑制劑對碳鋼表面吸附作用遵循Temkin's等溫吸附模式。除此之外由電化學測試之結果，顯示含HMTA抑制劑在進行酸洗時具有腐蝕抑制作用。除此之外本研究探討碳鋼表面粗糙度之變化並利用SEM觀察其表面形態的變化以探討腐蝕抑制劑對表面粗糙度之影響。

Pickling inhibitors can be used to form an adsorbed layer on the metal surface to hinder the discharge of H and dissolution of metal ions. Hexamethylenetetramine (HMTA) was selected as corrosion inhibitors for mild steel (MS) in pickling acid process. In this study, the addition of HMTA as the inhibitor, the pickling temperature and the pickling time were the parameters to investigate the effect on the inhibition efficiency (IE) and corrosion behavior for MS using weight loss measurement. The results showed that the IE increases with the increase in pickling immersion time and the increase in temperature at the room temperature and at 40℃. At the higher temperatures, the IE values were higher and almost independent of the pickling time. The adsorption of hexamethylenetetramine on the MS surface in hydrochloric acid was found to obey Temkin's adsorption isotherm. The potentiodynamic polarization studies were carried out at room temperature and revealed that the inhibitor blocked the corrosion reactions. The roughness test and SEM investigation were also studied in this paper.