Civil and Environmental Engineering Department, Virginia Tech, 407 Durham Hall, Blacksburg, Virginia 24061, USA.
Environ Sci Technol. 2010 Sep 15;44(18):7076-81. doi: 10.1021/es1015185.
As stagnant water contacts copper pipe and lead solder (simulated soldered joints), a corrosion cell is formed between the metals in solder (Pb, Sn) and the copper. If the resulting galvanic current exceeds about 2 μA/cm(2), a highly corrosive microenvironment can form at the solder surface, with pH < 2.5 and chloride concentrations at least 11 times higher than bulk water levels. Waters with relatively high chloride tend to sustain high galvanic currents, preventing passivation of the solder surface, and contributing to lead contamination of potable water supplies. The total mass of lead corroded was consistent with predictions based on the galvanic current, and lead leaching to water was correlated with galvanic current. If the concentration of sulfate in the water increased relative to chloride, galvanic currents and associated lead contamination could be greatly reduced, and solder surfaces were readily passivated.
当死水接触铜管和铅焊料（模拟焊点）时，在焊料（Pb、Sn）中的金属和铜之间会形成腐蚀电池。如果由此产生的电流超过约 2μA/cm2，则在焊点表面会形成腐蚀性极强的微环境，pH 值<2.5，氯离子浓度至少比水体高 11 倍。氯离子含量较高的水往往会维持较高的电流，防止焊料表面钝化，并导致饮用水中铅污染。根据电流预测，腐蚀的铅总量与水中的铅浸出量一致。如果水中硫酸盐的浓度相对于氯离子增加，电流和相关的铅污染可以大大减少，并且焊料表面很容易钝化。
