Stainless steel can be cathodically protected using energy stored at the marine sediment/seawater interface

ORFEI, LEDA HILEN; SIMISON, SILVIA; BUSALMEN, JUAN PABLO

ENVIRONMENTAL SCIENCE & TECHNOLOGY

American Chemical Society

Lugar: Washington; Año: 2006 vol. 40 p. 6473 - 6478

0013-936X

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 onlysource 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 cathodicprotection 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 stainlesssteels in seawater.