Stainless steels can be cathodically protected using energy stored at the marine sediment/seawater interface.
Laboratory-scale experiments were performed in which the corrosion protection of stainless steels in seawater was afforded by cathodic protection. The method was implemented for the first time using the potential difference at the marine sediment/seawater interface as the only source of electric power. Graphite electrodes buried in marine sediment, developing a potential of -0.45 V versus a saturated calomel electrode (SCE), were used as anodes to cathodically polarize UNS S30403 stainless steel coupons that were exposed to seawater. The cathodic protection system was operated with low polarization of stainless steel, typically to -0.2 V (vs SCE) and was found to properly prevent material failure even in the presence of a well-developed biofilm. With voltammetry, the protection current was found to be related to the oxidation of reduced sulfur compounds in the sediments. Results demonstrate that this inexpensive and environmentally friendly method can, so far, extend the service life of stainless steels in seawater.
Orfei
Leda H
LH
Laboratorio de Bioelectroquímica, División Corrosión, INTEMA-CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, B7608FDQ Mar del Plata, Argentina.
Simison
Silvia
S
Busalmen
Juan Pablo
JP
D018441:Biofilms; D003343:Corrosion; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology; D013193:Stainless Steel / Q000737:chemistry*
D013193:Stainless Steel