SnAgCu焊料中Sn元素在模拟土壤溶液中的浸出行为

研究了Sn-3.5Ag-0.75Cu无铅焊料及其与Cu基板的钎焊接头在模拟土壤的NaCl,NaCl-Na2SO4和NaCl-Na2SO4-Na2CO3溶液中Sn元素的浸出行为.结果表明:焊料在NaCl-Na2SO4-Na2CO3溶液中Sn的浸出相对严重;而接头在NaCl溶液中Sn的浸出量最多.在Sn浸出量多的焊料和接头表面形成厚而疏松的腐蚀产物,XRD分析表明其产物主要由SnO,SnO2和Sn4(OH)6Cl2组成.动电位极化测试分析表明接头中Cu基板与焊料合金之间的电偶腐蚀是焊料合金与接头在同种溶液中Sn元素浸出差异的主要原因.

Leaching of Su from SnAgCu solder in simulated soil solutions

Leaching behavior of Sn from Sn-3.5Ag-0.75Cu solder alloy and its joints with Cu substrate in three types of simulated soil solutions,namely NaCl,NaCl-Na2SO4 and NaCl-Na2SO4-Na2CO3 was investigated.It was found that serious leaching of Sn in the NaCl-Na2SO4-Na2CO3 solution was observed for the Sn-3.5Ag-0.75Cu solder,while for the Sn-3.5Ag-0.75Cu/Cu joint the largest leaching amount of Sn was realized in the NaCl solution.Thick and loosen corrosion products formed on the surface of solder and its joints where the leaching had severely occurred.From the XRD analysis,it revealed that the corrosion products were mainly composed of SnO,SnO2 and Sn4(OH)6Cl2.Based on the potentiodynamic polarization plots,it was proposed that the galvanic corrosion between solder alloy and Cu substrate was responsible for the leaching difference between solder and its joint.