Study of corrosion inhibition phenomena in acidic media by electrochemicaland surface analysis techniques

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 invest igated during polarization measurements as a function of inhibitor concentr ation. The Armco iron surface is studied by scanning electron microscopy, F ourier transform infrared reflection-absorption spectroscopy, and X-ray pho toelectron spectroscopy techniques. Anodically pre-polarized and non-polari zed specimens are investigated. The non-polarized specimens were immersed i n the aggressive solution for different time periods. It is found that the inhibition efficiency of different aminophosphonic acids can be increased b y halide ions. In the presence of aminophosphonic acids, the anomalous beha vior of halide ions can be eliminated during anodic polarization.