铁细菌对供水系统金属管材腐蚀行为的影响

Effect of Iron Bacteria on Corrosion Behavior of Metal-Pipe Materials in Water Supply System

铁细菌(iron bacteria,IB)是供水系统中影响金属管材腐蚀的主要微生物。从实际运行供水管道中提取IB,选用304不锈钢、316不锈钢、Q235碳钢和球墨铸铁,采用电化学分析、表面分析等方法,研究IB对上述管材腐蚀行为的影响。结果表明,IB体系中304不锈钢、316不锈钢的腐蚀速率在试验周期内随时间增加逐渐增大,Q235碳钢、球墨铸铁腐蚀速率则先快速增大后逐渐减小。IB体系中304不锈钢、316不锈钢表面产生较薄腐蚀层,球墨铸铁表面存在大量腐蚀产物和IB,Q235碳钢表面发现少量产物。球墨铸铁和Q235碳钢的腐蚀产物主要为磁铁矿、针铁矿、镁铁氧化物,但这些腐蚀产物在304不锈钢、316不锈钢表面未检出。IB对4种管材的腐蚀作用排序为:球墨铸铁>Q235碳钢>304不锈钢>316不锈钢。

Iron bacteria(IB)is the main microorganism that can affect the corrosion of metal-pipe materials in the water supply system.IB was extracted from the actual running water supply pipelines.304 stainless steel,316 stainless steel,Q235 carbon steel,and ductile iron were selected to study the effect of IB on their corrosion behavior according to electrochemical analysis,surface analysis,and other methods.The results showed that the corrosion rate of 304 stainless steel and 316 stainless steel in the IB system gradually increased during the whole tested period,while the corrosion rate of Q235 carbon steel and ductile iron increased rapidly earlier stage and decreased gradually later.In the IB system,a thinner corrosion layer,a large amount of corrosion products and IB cells,and a small amount of corrosion products were found on the surface of 304 stainless steel and 316 stainless steel,ductile iron,and Q235 carbon steel,respectively.The corrosion products of ductile iron and Q235 carbon steel were mainly magnetite,goethite,and magnesium iron oxide.However,the corrosion products were not detected on the surface of 304 stainless steel and 316 stainless steel.The promotion effect of IB on corrosion behavior of four metal-pipe materials was as follows:ductile iron>Q235 carbon steel>304 stainless steel>316 stainless steel.