Influencia de los iones nitrato en la corrosión de la Aleación 22
Resumen
La aleación 22 (N06022) pertenece a la familia de aleaciones Ni-Cr-Mo, su base es el níquel y tiene un alto contenido de cromo (~22%) y molibdeno (~13%). Diversos estudios muestran que la aleación 22 es resistente a la corrosión generalizada y localizada (en rendijas) en soluciones acuosas, con altas concentraciones de cloruro y un amplio rango de temperaturas.
Para este trabajo se aplicaron técnicas electroquímicas, tales como Espectroscopia de Impedancia Electroquímica (EIS) y ensayos Potenciodinámicos-Galvanostáticos-Potenciodinámicos (PD‑GS‑PD), además de técnicas complementarias no electroquímicas, como Microscopia Electrónica de Barrido, para determinar el efecto de los iones nitrato y cloruro sobre la corrosión generalizada y localizada de la aleación 22 a 90 oC.
Los resultados muestran que para la relación molar crítica R= [NO3 -]/ [Cl-] ≥0.2 se elimina completamente la susceptibilidad de la aleación 22 a la corrosión en rendijas. Las velocidades de corrosión obtenidas fueron del orden de 0.1 μm/año a 24 horas de inmersión.
Palabras clave
aleación 22, Corrosión en rendijas, Nitratos, Potencial de repasivación, PD-GS-PD
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