Pitting Corrosion Evaluation of Titanium in NH₄Br Solutions by Electrochemical Methods

摘要

Anomalous pitting sensitivity of titanium in ammonium bromide solutions was detected. Undersaturation conditions pitting was not observed visually after anodic polarization and positive hysteresisloop was not recorded. Electrochemical impedance spectroscopy (EIS) shows an increase in resistancewith time without an inductive element in the equivalent electrical circuits. This anomalous behavior- may be related to changes in the molecular structure of the OH bonds under saturation. In diluteammonium bromide solutions, a pitting attack was observed visually after anodic polarization and cyclicpolarization had shown a positive hysteresis loop. EIS shows an inductive loop related to the active pitsthat exist on the anodic surface.