焊料在NaCl溶液中重金属元素的浸出行为

电子垃圾填埋时重金属元素的浸出会造成环境和地下水的污染,进而危害人类的健康。文章以Sn-0.75Cu、Sn-3.5Ag-0.75Cu和Sn-37Pb焊料合金及接头作为对象,研究了它们在3.5%NaCl溶液中重金属元素的浸出行为。结果表明,3种焊料合金浸出后Sn的浸出量差别不大,而3种钎焊接头Sn的浸出量却高出焊料合金中浸出量的1个数量级,并且无铅钎焊接头中Sn的浸出量高于Sn-37Pb钎焊接头;焊料合金中Ag、Cu的浸出量较少,Pb的浸出量较高,而钎焊接头中Ag、Cu及Pb的浸出量均高于焊料合金。焊料合金在NaCl溶液中浸出后表面生成的腐蚀产物较少,而钎焊接头浸出后表面生成的腐蚀产物却很多,其产物主要是由SnCl2、Sn(4OH)6Cl2和PbC(lOH)相组成。

Leaching Behavior of Heavy Metals from Solder and Their Joints in a NaCl Solution

The environment and underground water will be polluted by heavy metal elements which leached out from the solder during the process of electronic wastes landfill.The leaching behavior of heavy metal elements from three widely used solder alloys and their joints in 3.5% NaCl solution,namely Sn-0.75Cu,Sn-3.5Ag-0.75Cu and Sn-37Pb was therefore investigated.Results showed that the leaching amount of Sn had no obvious difference between these three solder alloys.After soldering,however,the amount of Sn released from the solder joints was almost one order of magnitude higher than that of solder alloys.Moreover,the leaching amount of Sn from lead-free solder joint was higher than that from Sn-37Pb joints.The leaching amount of Ag and Cu from solder alloys was lower than that of Pb and the amount of these three elements leached from the solder alloys was also higher than that from solder alloys.Less corrosion product formed on the surface of solder alloys leaching in NaCl solution,while more corrosion products formed on the surface of solder joints after leaching,which is mainly composed of SnCl2,Sn4(OH)6Cl2 and PbCl(OH) phase.