Abstract

The inhibition performance of 5-methyl-3-phenylisoxazole-4-carboxylic acid (MPC) alone and in combination with potassium iodide (KI) for low carbon steel in 1.0 M HCl and H₂SO₄ solutions is studied using weight loss, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), ultraviolet–visible (UV–vis) spectrophotometry, and surface observation methods. The influence of solution temperature on the performance of MPC and MPC + KI is also investigated. Results obtained indicate that the optimum concentration of MPC in 1.0 M HCl and H₂SO₄ solutions is 500 and 50 mg/L, respectively. The maximum inhibition at the optimum concentrations of MPC in HCl and H₂SO₄ solutions at 25 °C is 46 and 23%, respectively. Addition of 3 mM KI to 500 mg/L MPC in HCl solution and to 50 mg/L MPC in H₂SO₄ solution at 25 °C raised the inhibition efficiency to 86 and 89%, respectively. Inhibition efficiency of MPC and MPC + KI increases with rise in solution temperature with MPC + KI inhibition reaching 88 and 91%, respectively in HCl and H₂SO₄ solutions at 60 °C. Both MPC and MPC + KI acted as a mixed-type corrosion inhibitor according to the PDP results. Surface examination results confirm the effectiveness of MPC + KI mixture in retarding low carbon steel corrosion in 1.0 M HCl and H₂SO₄ solutions. It could be profitable utilizing MPC + KI mixture in the formulation of corrosion inhibitor cocktail for acid cleaning operations.

摘要

采用失重法、动电位法研究了 5-甲基-3-苯基异恶唑-4-羧酸 (MPC) 单独和与碘化钾 (KI) 组合在 1.0 M HCl 和 H ₂ SO ₄溶液中对低碳钢的缓蚀性能极化（PDP）、电化学阻抗谱（EIS）、线性极化电阻（LPR）、紫外-可见（UV-vis）分光光度法和表面观察方法。还研究了溶液温度对 MPC 和 MPC + KI 性能的影响。结果表明，MPC 在 1.0 M HCl 和 H ₂ SO ₄溶液中的最佳浓度分别为 500 和 50 mg/L。MPC 在 HCl 和 H _{2中的最佳浓度下的最大抑制}25 °C 时的SO ₄溶液分别为 46% 和 23%。在 25 °C下，将 3 mM KI 添加到 500 mg/L MPC 的 HCl 溶液和 50 mg/L MPC 的 H ₂ SO ₄溶液中，抑制效率分别提高到 86% 和 89%。MPC 和 MPC + KI 的抑制效率随着溶液温度的升高而增加，在 60 °C的 HCl 和 H ₂ SO _{4溶液中，MPC + KI 的抑制率分别达到 88% 和 91%。}根据 PDP 结果，MPC 和 MPC + KI 均作为混合型缓蚀剂。_{表面检测结果证实了 MPC + KI 混合物在 1.0 M HCl 和 H 2} SO ₄中延缓低碳钢腐蚀的有效性解决方案。使用 MPC + KI 混合物配制用于酸洗操作的缓蚀剂混合物可能是有利可图的。