Research On The Corrosion Characteristics Of Sulfate Reducing Bacteria In Jet Fuel

The pure strain SRB is isolated and purified by microbiological methods from the initialstrains. SRB was identified as gram negative bacteria by detection technology.Variation of thenumber of SRB in medium at different time were measured by method of the most probablenumber (MPN). Growth curve of bacteria was described in order to gain the vegetal rule ofbacteria (divided into four periods：logy periods，logarithmic growth periods，steady growthperiods，contabescence periods).The metal hanging sheet of X70pipeline steel and2024-T31aluminium-magnesiumalloy are soaked in the medium with bacteria and sterile medium for30d, then to observe themacroscopic and micro corrosion morphology of these two kinds of metal in differentcorrosion stages and analyse the composition of corrosion products. The results show that:SRB participate the corrosion of the matrix and the element S is detected in the corrosionproducts of two kinds of metal.2024-T31aluminium-magnesium alloy corrosion resistance isbetter than that of X70pipeline steel.The working electrode soaked in the medium with bacteria and sterile medium arestudied by polarization curves and electrochemical impedance spectroscopy technique.Results show that SRB can produce the biofilm which can isolate the inside and outsidesubstances of the matrix, leading to forming local anaerobic zone in the surface of the matrix，which can promote the growth of SRB and accelerate the corrosion of the matrix; Thecausticity of matrix is the strongest at the initial stage of immersion，then which is graduallyweakened with the extension of soaking time;The existence of SRB block the anodic process，and promote the cathodic depolarization.