Biocorrosão marinha: a comunidade macroincrustante e seu efeito na corrosão de aços inoxidáveis especiais de alta liga (AISI 316, AISI 904l e Zeron 100)

Abstract

Metallic materials expose to marine environment are susceptible to the growth of biofouling on the surfaces immersed. The main goal of this work was to verify the effects of biofouling, especially barnacles in high-alloyed stainless steels (AISI 904L, Zeron 100 e AISI 316) used in marine systems. Two experiments were assembled: a field experiment, where the coupons were immersed for 285 days hung over rafts in Cabo Frio Island (Arraial do Cabo), in which open circuit potential and the percentage cover of biofouling were estimated. The second was done in laboratory and the aim was to estimate the open circuit potential, breakdown potential and to acquire impedance diagrams associated to the attachment and initial development of the barnacle Balanus amphitrite, which larvae were cultivated until the attachment stage. The results obtained did not allow compare the AISI 316 steel with the high-alloyed stainless steels. Therefore, based on the breakdown potential values obtained in polarization tests and the Nyquist diagrams, it was possible to conclude that 904L steel was more susceptible to localized corrosion caused by biofouling than Zeron 100.