How to Determine Lead-Free vs. Lead-Solder Paste

I. Appearance Assessment

Lead-free solder paste differs in appearance from leaded solder paste. Generally, leaded solder paste is silver-white, with a certain sheen, lighter in color, and softer in texture, prone to deformation, while lead-free solder paste is gray or light gray.

II. Ingredient Assessment

Lead-free and leaded solder paste differ in composition, which can be identified through component analysis. Leaded solder paste typically contains the Pb element, whereas lead-free solder paste does not contain Pb and is usually composed mainly of Sn, Ag, Cu, and Bi.