Anticorrosion propriety of new resin epoxy derived from phosphorus as inhibitor of steel corrosion in 0.5 M H2SO4

•This study is for aim to evaluate the performance of PBA resin as corrosion inhibitor.•This study performed for the carbon steel in acidic medium (0.5 M H2SO4) at room temperature, by the weight loss and electrochemical methods and the surface investigated using SEM/EDS and AFM.•The results showed that the corrosion inhibition behavior of inhibitor is excellent in sulfuric acid.•The experimental result confirmed by a theoretical study. This paper aims to study the performance of the pentaglycidyl ether pentabisphenol A of phosphorus (PBA) as corrosion inhibitor for carbon steel (E24) in 0.5 M H2SO4. This study has performed using gravimetric measurements, electrochemistry measurements such as potentiodynamic and electrochemical impedance spectroscopy techniques, and surface analysis (SEM/EDS). The results show that the PBA has good anticorrosive behavior against the 0.5 M H2SO4 solution; the inhibition efficiency reached 96.25% for 10−3 M of PBA. The adsorption isotherm of Langmuir indicates the existence of a chemical chemisorption of the PBA on the metal surface (∆G* = –44.23 Kj/mol). The nature and properties of the protective layer on the steel surface were verified by scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDX).