Dull Solder Surface

Lead-free solders frequently display, after having solidified, a dull surface. This occurs on account of the alloying elements, the cool down gradient and the solder volume of the solder joint, and it is normal. If tin/lead solders display a dull surface after cool down, this points to a problem during the cool down phase, or to insufficient temperatures (in the reflow process) on the solder joint. Tin/lead solders as a rule solidify displaying a high gloss.