7075-T6镁铝合金的微生物腐蚀行为研究

摘要

采用电化学方法研究了7075-T6镁铝合金在含有微生物的航煤溶液中的腐蚀行为。结果表明：微生物的存在使得镁铝合金的自腐蚀电位时而正移时而负移，溶液中的pH值下降，合金的耐蚀性降低；浸泡前期，电极表面形成的生物膜均匀致密，可以减缓基体的腐蚀；浸泡后期，生物膜破裂，加速了阴极去极化作用，基体腐蚀加速；生物膜的不断生成和破裂，使得溶液中的离子及溶解氧扩散到电极表面，导致腐蚀持续加速进行。%The corrosion behaviors of 7075-T6 magnesium aluminum alloy in aviation kerosene solution with microorganisms were studied by corrosion potential, electrochemical impedance spectra, polarization curves, etc. Results show that the presence of microorganisms make the corrosion potential of magnesium aluminum alloy sometimes positive shift and sometimes negative shift , the pH value of solution decline, the decrease of magnesium aluminum alloy‘s corrosion resistance. At the early stage of the soak, the biofilm formed on the electrode surface is uniform and dense, which can slow down the corrosion of the matrix. Later, the biofilm rupture and accelerate the cathodic depolarization and the corrosion rate of the matrix. Continuous formation and rupture of biofilm, making the ions and dissolved oxygen of the solution diffuse to the electrode surface, causing corrosion sustained acceleration.