Basic Requirements for Lead-free Electronic Solder for Electronic Assembly (Part 2)

Melting point Most assembly manufacturers (not all) require a minimum solid phase temperature of 150 C to meet the working temperature requirements of electronic equipment, and the maximum liquid phase temperature depends on the specific application.

Good conductivity is the basic requirement of solder for electronic connection.

In order to emit heat energy, electronic solder must have fast heat transfer ability.

Amorphous alloys solidify in a temperature range between liquid temperature and solid temperature within a small range of solid-liquid coexistence temperature. Most metallurgical experts recommend that this temperature range be controlled within 10 C in order to form good solder joints and reduce defects. If the solidification temperature range of the alloy is wide, the solder joint cracking may occur and the equipment will be damaged prematurely.

Low toxic electronic solders and their components must be non-toxic, so this requirement excludes cadmium, thallium and mercury from consideration; some people also require that by-products extracted from toxic substances should not be used, thus excluding bismuth, because bismuth mainly comes from by-products extracted from lead.