Tetrahydroacridines as corrosion inhibitor for X80 steel corrosion in simulated acidic oilfield water

X80 steel is commonly used in pipeline, tubing, casing and other facilities in oilfield construction. Its corrosion behaviors in 15% HCl without or with tetrahydroacridines was investigated by weight-loss tests, electrochemical techniques along with scanning electron microscope (SEM)/energy dispersive spectroscopy (EDX), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). The experimental results indicated that tetrahydroacridines have excellent inhibitive performance for X80 steel in 15% HCl, and the ηmax of MPTA and EPTA reached up to 97.87% and 95.96% at 400 ppm, respectively. The properties of tetrahydroacridines are mixed-type based on polarization studies, and the adsorption mode follows Langmuir isotherm and physical adsorption is dominant. On the basis of surface analysis and characterization, the formation and characteristic of an adsorption-related protective inhibitor film on the X80 steel surface have been verified.