Lead-Free Solder Paste

 

The worldwide search for an effective lead-free solder may be over as Ames Lab's new environmentally friendly option begins reaching the marketplace.

For centuries, tin-lead solders have been the standard for low-temperature bonding of metals, but now industry needs another choice. Hazardous to human health, lead in solder presents risks in the workplace and at the landfill where soldered electronic boards routinely end up. In fact, the U.S. Environmental Protection Agency has identified lead in discarded electronics as a groundwater contaminate, legislation has been proposed to eliminate lead from solder, and industry experts predict regulation of lead solder is on its way.

"While our solder is lead-free and reduces the environmental hazard, that's not its only advantage," says Ames Lab's Iver Anderson, co-inventor of a new solder from tin, silver and copper. "We worked with different alloy combinations and solidification processes to find a unique composition that retains many qualities of tin-lead solders but offers improvements too, such as greater strength and heat resistance," explains Anderson.

Testing solderability and strength, collaborators on the project at Sandia National Laboratory have confirmed that the new solder will apply easily like traditional solders yet offer increased strength important for withstanding the rugged environments of today's high-tech applications. A slightly higher melting point, within the operating range of current soldering equipment, is another advantage of the new solder -- making it less likely to fail in high-temperature settings like under the hood of an automobile.

While other lead-free solders are under development, the availability and cost of the metals in this new solder coupled with its outstanding properties make it a particularly attractive replacement for tin-lead. Commercial solder manufacturers seem to agree. One company is already producing this new solder for use in heavy-equipment radiators while another is finalizing the licensing process to produce the solder for a different application.


 

BENEFITS:

  • Environmentally Friendly - Unlike traditional solder, Ames Lab's new solder contains no lead. It also contains no by-products of lead mining as some other lead-free options do.
  • Increased Strength - A finer microstructure allows this solder to withstand greater stress and more rugged settings, than traditional solders.
  • More Temperature-Resistant - Unlike traditional solders, this can withstand higher-temperature environments and the thermomechanical fatigue of dramatic temperature changes, both common in today's high-tech machinery.
  • Resists Corrosion - Unlike tin-lead, this solder is not sensitive to corrosion, which can weaken a soldered connection.
  • Easy to Work With - Like traditional solder, but unlike many other lead-free options, this applies to metals easily and can be formed into sheets or wires for accurate placement.
  • Inexpensive and Available - While slightly more expensive than tin-lead, the metals of this solder (tin, silver and copper) are abundant and less expensive than most other lead-free solders under development.

BOTTOM LINE:

The strength, heat resistance, workability and cost-effectiveness of Ames Lab's new lead-free solder make it an attractive alternative for getting environmentally hazardous lead out of commonly used solders.


FOR MORE INFORMATION:

Iver Anderson, e-mail: andersoni@ameslab.gov, phone: (515) 294-9791