海滨盐碱土壤中硫酸盐还原菌对X100管线钢腐蚀行为的影响

Effect of Sulfate Reducing Bacteria on Corrosion Behavior of X100 Pipeline Steel in Seaside Saline-Alkali Soil Simulated Solution

为了进一步明确X100管线钢在含硫酸盐还原菌(SRB)海滨盐碱土壤中的耐蚀性,采用表面分析技术、电化学技术和失重法,研究了SRB对X100管线钢腐蚀过程与行为的影响。结果表明:X100管线钢在有无SRB海滨盐碱土壤中的腐蚀均属于中度腐蚀,无SRB时腐蚀产物主要为Fe_2O_3,Fe_3O_4和γ-Fe O(OH),有SRB时腐蚀产物主要为Fe_2O_3,Fe_3O_4,α-Fe O(OH)和Fe7S8;SRB代谢形成的活性生物膜影响了X100管线钢的腐蚀行为,随着腐蚀时间的增加,SRB可在X100管线钢表面形成由微生物膜与腐蚀产物结合的膜,其更加致密,对腐蚀传质具有物理阻碍作用,可以减缓X100管线钢的腐蚀;无SRB菌时X100管线钢表面的腐蚀产物疏松多孔并分布有裂纹,且对基体的保护作用差,其腐蚀速率大于有SRB时的值;SRB的代谢活动抑制了X100管线钢的腐蚀。

In order to define the corrosion resistance of X100 pipeline steel in saline-alkali soil with sulfate reducing bacteria （SRB）,the effect of SRB on corrosion process and behavior of X100 pipeline steel was investigated in seaside saline-alkali soil solution by surface analysis techniques,electrochemical techniques and weight loss method.Results showed that the X 100 pipeline steel presented a moderate corrosion rate in seaside saline-alkali soil solution with the presence and absence of SRB.The corrosion products in soil solution without SRB were Fe2O3,Fe3O4 and γ-FeO（OH）,while those with SRB were Fe2O3,Fe3O4,α-FeO（OH） and Fe7S8.The active biofilm generated by SRB metabolite activity influenced the corrosion behavior of X100 pipeline steel.With the increase of corrosion time,the integrated film of microbial film and corrosion products together formed bv SRB on the X100 steel substrate surface became more compact,which could block the corrosion mass transfer and then reduce the corrosion rate of X100 steel.However,the corrosion product film in soil solution without SRB was loose,uneven and cracked,and exhibited poorer protective function on the steel substrate,causing that the corrosion rate was higher than that in the soil with SRB.Furthermore,these results suggested that SRB inhibited the corrosion of X100 pipeline steel.