Effect Of Pseudoalteromonas Piscicida Sp. On Metal Corrosion Behavior In Marine Environment

The sea is far from full development of natural resources,and high salt,high humidity,fluctuation,microbial activities under the marine environment is very corrosive,which traditional materials of marine engineering its weak corrosion resistance cannot resist water erosion,there is huge maintenance costs and even catastrophic consequences.In addition to the commonly used coating,media processing,electrochemical protection and other methods,this paper from the bacterial perspective,by exploring the Pseudoalteromonas piscicida sp.effect on several kinds of common metal materials corrosion behavior,to discuss the possibility of using microbial inhibition corrosion method.Mainly by using electrochemical method and surface analysis method,qualitative and quantitative technology,biological methods to study the changes in the corrosion behavior of Q235 A carbon steel,C95400 aluminum bronze,pure titanium and HRB400 in hot rolled ribbed steel bar under the action of external loads in artificial sea water immersion test cycle containing Pseudoalteromonas piscicida sp.Found that:(1)Alternation of Pseudoalteromonas piscicida sp.could greatly improve the electrochemical impedance of Q235 A carbon steel in seawater,and the corrosion current and corrosion rate all decreased significantly.Scanning images showed that biofilm on the surface of carbon steel was generated.After the addition of bacteria,Pseudomonas aeruginosa could still maintain a high efficiency of corrosion inhibition;(2)C95400 aluminum bronze has good corrosion resistance due to its formation of aluminum oxide film in seawater,but its charge transfer resistance has been greatly improved under the condition of bacteria.The overlapping structure formed by biofilm and oxide film has greatly strengthened the corrosion resistance of aluminum bronze;(3)Pure titanium itself is not affected by seawater.But from the electrochemical results,the impedance radius of pure titanium is also increased,and the three-dimensional structure and thickness information of biofilm can be observed by laser confocal imaging;(4)The electrochemical impedance of HRB400 hot rolled ribbed bar values and polarization curves show that the corrosion resistance is enhanced,and the steel surface was completely mixed biofilm film and oxide covered no traces of corrosion under aseptic conditions,vertical to tensile stress direction;(5)The bacteria in common laboratory jar culture system,improve the metal corrosion resistance ability to simulate the marine environment system,this is because the corrosion of high velocity and high oxygen content of seawater will increase the first metal substrate,the structure will affect bacterial life and biofilm.The biofilm loose tight,can not block direct contact with the metal substrate and the seawater,corrosion inhibition weakened bacteria.The culture system of bacteria can quickly enter the logarithmic growth phase in the jar,the quantity of bacteria and extracellular polymers increased significantly make biofilm complete dense and evenly distributed on the surface of metal rapid formation,faster forming protective layer and the structure intact,preventing further corrosion of the matrix,which has good corrosion inhibition.FTIR also showed that bacteria could secrete amides(metal proteinases)which were only found in wide mouthed culture apparatus,which is another reason for the increase of metal corrosion resistance in jar.From above results,the Pseudoalteromonas piscicida sp.can significantly inhibit the corrosion process of common metal materials in seawater.