The pitting corrosion of supermartensitic stainless steel (SMSS) was studied in an aqueous solution of 0.1 mol/L NaCl using the scanning vibrating electrode technique (SVET) and cyclic voltammetry. The SMSS showed 0.9% of retained austenite, as verified by Mössbauer spectroscopy. Cuboidal TiN particles were identified on the steel surfaces, by using optical, scanning electron, and transmission microscopy, associated to Mg-Ca-Al rich precipitates. Pit nucleation was slow and only verified after 24 h, associated to TiN/CaO·MgO·Al2O3 complex inclusions, thus on original interdendritic spaces, where lower Cr content and the presence of inclusions are expected.

Soil corrosion of carbon steel samples buried up to hundred days close to a high voltage power transmission line tower was examined by weight loss vs. time. A higher weight loss was observed if the samples were electrically connected to the tower than if they were not. This was attributed to the influence of alternating current (AC) signals induced in the soil by the transmission line. This field study showed for the first time the influence of the AC power line on the buried structure of the tower, while other studies so far were focused only on AC corrosion of cathodically protected coated pipelines, running parallel to the transmission line. An improved method was used to measure weight loss by descaling in Clark solution. The new method substitutes discontinuous measurements, proposed in the ASTM-G1-90 standard, by in situ measurements of the weight loss during descaling, using a computer controlled microbalance.