Corrosion inhibition properties of iodide ionic liquids for API 5L X52 steel in acid medium

[Display omitted] •The compounds [DBIM]+I− and [DPIM]+I− work as mixed-type inhibitors.•The inhibition efficiency of [DBIM]+I− and [DPIM]+I− is a function of the concentration and Reynolds number.•The ionic liquids [DBIM]+I− and [DPIM]+I− obey the Langmuir isotherm, confirming physical-chemical adsorption.•Inhibition efficiency results were supported by SEM, AFM, computed tomography and XPS surface analyses.•The orientation of [DBIM]+I− and [DPIM]+I− was mainly by the anion iodide. A mechanism for describing the corrosion inhibition of API 5L X52 steel in 1 M H2SO4 employing two ionic liquids (ILs) with imidazolium-derived cations and iodide anion as corrosion inhibitors (CIs) at stationary and dynamic states is proposed. The adsorption process occurred firstly through the adsorption of iodide ions (I−) on the metal surface as a result of the coulombic force, which promoted the subsequent adsorption of the imidazolium cation. The maximal inhibition efficiency (IE) values for the ILs ranged from 91 to 95 %. Likewise, the XPS, computed tomography, SEM and AFM results supported the obtained IEs.