Corrosion behavior of B10 copper-nickel alloy beneath a deposit caused by sulfate-reducing bacteria with carbon source starvation in marine environments

Copper-nickel alloys can suffer severe localized corrosion in marine environments containing sulfate-reducing bacteria (SRB), but the effect of SRB on the under-deposit corrosion of copper-nickel alloys is unknown. In this work, the corrosion behavior of B10 copper-nickel alloy beneath a deposit caused by SRB with carbon source starvation in artificial seawater was studied based on electrochemical measurements and surface analysis. Results demonstrate that SRB with an organic carbon starvation can survive in artificial water but most SRB cells have died. The survived SRB cells can attach to the bare and deposit-covered B10 copper-nickel alloy, leading to the corrosion acceleration. Due to the limitation of organic carbon source, the pitting corrosion of B10 copper-nickel alloy caused by SRB is not serious. However, serious pitting corrosion of the deposit-covered B10 copper-nickel alloy can be found both in abiotic and biotic conditions, and the pitting corrosion and uniform corrosion are further accelerated by SRB. There is a galvanic effect between the bare and deposit-covered specimens in the presence of SRB in the early stage but the galvanic effect after 5 d of testing can be neglected due to the low OCP difference values.