Effect of Chloride-to-sulfate Mass Ratio on Galvanic Corrosion of Brass-Lead Joints
Taking the galvanic coupling connection of brass and lead soldering in water distribution system as the object,the effect of different chloride to sulfate mass ratio(CSMR)on the brass-lead galvanic corrosion was investigated.The metal release,electrochemical behavior and corrosion products of the brass-lead galvanic corrosion were analyzed.The results show that CSMR makes the anodic polarity change in the multi-electrode pairs.At CSMR of 0-0.5,lead and zinc are acted as anode simultaneously;at CSMR=1,zinc is acted as anode alone;and at CSMR=∞,lead is acted as anode alone.The corrosion products of lead are PbCO3 in the form of rods and Pb3(CO3)2(OH)2 in the form of flakes.The product of zinc is flat ZnO2,the product of copper is granular Cu2O,and the product of tin is lumpy SnO2.When brass is galvanic connected to lead-containing material in the water supply pipeline,it is recommended to control the CSMR around 1 to reduce the release of lead.
chloride to sulfate mass ratio(CSMR)brassleadgalvanic corrosion
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