INFLUENCE OF CHLORIDE AND HUMIDITY ON MECHANICAL STRENGTH OF TIN- LEAD SOLDER

The Influence of humidity and chlorine on mechanical strength of fresh and reused tin–lead solder (solder dross) was investigated. Solidification rate and temperature profile was also discussed. Calculation showed that the solder solidified almost instantly.

Butt, simple lap and double lap joints of copper were prepared. No- clean flux rosin and solder mask with the thickness control of solder joint were implemented.

Salt spray fog test for sets of tin- lead joints was carried out. Samples exposed for different time was subjected to shear and tensile tests. The strength of the fresh and reused solder decreased with exposure time. White substances were found precipitated at the edges of the solder joint. X-ray diffraction analysis showed that these substances were PbCl₂ and PbCO₃. This result indicated that Cl^- ions attacked Pb in the solder and formed white porous substances that would weaken the strength of tin – lead solder.