Pitting corrosion control using regenerative biofilms on aluminium 2024 inartificial seawater

EIS has been used to follow the pitting process of Al 2024 during exposure to sterile artificial seawater (AS) for 30 days. In the presence of a bacte rial biofilm produced by Bacillus subtilis pitting was also observed during the first two days. however for the remainder of the exposure period the A l alloy was passive. When the biofilm was genetically engineered to secrete polyglutamate or polyaspartate, an additional small increase in corrosion inhibition occurred. Corrosion control using regenerative biofilms (CCURB) on Al 2024 in AS cannot be solely due to a reduction of the oxygen concentr ation at the metal surface since the experimental values of the corrosion p otential E-corr became more noble in the presence of bacteria suggesting th at production of an inhibiting species retained in the biofilm contributes to CCURB. (C) 2001 Elsevier Science Ltd. All rights reserved.