The kinetics of iron dissolution in sulfuric acid solutions is investigated by polarization measurements in the presence of halide ions and/or organic additives. Both the inhibition action and additive interactions are investigated during polarization measurements as a function of inhibitor concentration. The Armco iron surface is studied by scanning electron microscopy, Fourier transform infrared reflection-absorption spectroscopy, and X-ray photoelectron spectroscopy techniques. Anodically pre-polarized and non-polarized specimens are investigated. The non-polarized specimens were immersed in the aggressive solution for different time periods. It is found that the inhibition efficiency of different aminophosphonic acids can be increased by halide ions. In the presence of aminophosphonic acids, the anomalous behavior of halide ions can be eliminated during anodic polarization.
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