Study of the sensitisation process of a duplex stainless steel (UNS 1.4462) by means of confocal microscopy and localised electrochemical techniques

When duplex stainless steels are heated, they can become sensitised and intermetallic phases can appear. In this work, samples of duplex stainless steel, UNS 1.4462, have been heated (850 degrees C for 1 and 2 h) in a heating unit that can be accommodated to a confocal microscope in order to study the morphological changes in-situ. The electrochemical behaviour of the samples has been analysed by means of conventional and localised electrochemical techniques. According to the results, there is a general decrease in the steel resistance to localised corrosion; this decrease can be related to defects in the formed passive film.We wish to express our gratitude to MICINN (CTQ2009-07518), to Universitat Politecnica de Valencia (CEI-01-11), to the Generalitat Valenciana for its help in the CLSM acquisition (MY08/ISIRM/S/100), to Professor Alda Simoes and Andreia Marques for the help on LEIS measurements and to Dr. Asuncion Jaime for her translation assistance.Leiva García, R.; Fernandes, JS.; Muñoz-Portero, M.; Garcia-Anton, J. (2015). Study of the sensitisation process of a duplex stainless steel (UNS 1.4462) by means of confocal microscopy and localised electrochemical techniques. Corrosion Science. 94:327-341. https://doi.org/10.1016/j.corsci.2015.02.016S3273419

Aging behaviour of lean duplex steel using thermoelectric power measurements

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Ablation time efficiency and lesion volume - in vitro comparison of 4 mm, non irrigated, gold- and platinum-iridium-tip radiofrequency ablation catheters

We investigated the development of in vitro lesion formation in relation to ablation time and power delivery using 4-mm, non-irrigated, platinum-iridium (Pt/Ir), and gold-tip catheters. Radiofrequency catheter ablation was performed on porcine liver preparations in a 5-60-s time range with 5 s increments applied at different lesion sites. Each series was repeated four times for both catheters. The lesion volume, the delivered energy, and the ablation power curves were analyzed in 96 ablations. The delivered energy was higher and the lesion volume was significantly larger when using a gold-tip catheter. The lesion volume that was created with the Pt/Ir-tip electrode within 60 s was created after a shorter 40 s ablation period with the gold-tip electrode (Au, 40 s, 345 +/- 75 mm(3) vs. Pt/Ir, 60 s, 328 +/- 30 mm(3)). The gold-tip catheters had a lower tip temperature resulting in higher energy delivery due to the better thermo-conductivity of the gold alloy. A significantly higher lesion volume and a faster lesion creation were found for gold catheters as compared to Pt/Ir catheters. Gold-tip catheters can create the same adequate lesion within 33.3 % less ablation time due to the higher values of delivered energy as compared to those observed with the use of Pt/Ir catheters