New insights into rusting
DELFT _ How fast does a steel hull rust? TNO _ the Dutch research organization in service of corporate competitiveness _ says it has developed new insights into rusting. If a hull rusts only due to oxidation of iron in the water, the decaying could take years. “But under influence of microorganisms, corrosion processes can happen in a matter of months,” says TNO scientist Felipe Leon Morales. “It is often difficult to include microbial corrosion in corrosion risk analyses (yet some) 20% of all corrosion damages are caused by micro-organisms.”
Corrosion research has accelerated since 5,000 barrels of oil leaked from an Alaska pipeline in 2006. The cause: a sediment at the bottom of the pipeline that was as breeding ground for acidic bacteria eating into the steel.
It is often assumed that brackish water, like that of the Baltic Sea, is less corrosive than that of open seas. But years of industrial pollution has pumped nutrients into the Baltic that feed microbial activity increasing the risk of corrosion.
TNO says it has developed rust diagnostic tools. If micro-organisms are the cause, the use of a biocide, to attack the microorganisms, is the answer. TNO is one of the few parties involved in this research. “We are involved in the whole spectrum of material analysis and also in the impact of microbial activity on material performance,” says Morales. With a better understanding of this phenomenon and a targeted solution, the industry can enjoy a longer life cycle of their products, spend less time on maintenance and prevent accidents, he adds.