Published on March 7th, 2010 | by Tina Casey7
New "Liquid Magnet" Solder Eliminates Toxic Lead
A team of researchers at Yale University has developed a new kind of magnetic, lead free solder that could be used to manufacture electronics more cheaply and efficiently. That would be a big boost for efforts to manage the growing problem of electronic waste disposal and recycling, because conventional solder is made from lead, a known health hazard.
Lead is a heavy metal that was commonly used in house paint and gasoline in the U.S. Those uses were banned after the discovery that lead is a potent neurotoxin, but lead solder continues to be permitted in U.S. manufacturing. That creates a huge problem in the electronic waste stream, and it also impedes U.S. companies from entering global markets where anti-lead regulations are growing.
The Lead Solder Conundrum
The key to lead’s popularity lies in the one-two punch of high strength combined with a low melting point. Lead solder can be melted directly onto delicate electronic components with a relatively small amount of heat, which greatly reduces the chance of damaging the components during the manufacturing process. As writer Katherine Bourzac describes in MIT’s Technology Review, so far the non-lead alternatives have failed on both counts: they tend to be weaker, and they require much more heat during the soldering process.
Yale’s Magnetic Solder Breakthrough
The Yale team has come up with a tin-silver alloy that holds micro-particles of iron. Rather than applying heat from an external source, the compound is exposed to a magnetic field. That excites the iron particles, which causes the solder to heat up and melt internally. The result is a highly localized melt that has little or no effect on the components around it. Bourzac explains that the magnetic field also forces the iron particles to line up. The particles hold position when the solder cools, which results in a much stronger bond than possible with conventional non-lead soldering compounds.
Magnets and Energy Efficiency
Magnets are beginning to establish a pivotal role in the energy efficient future. At Columbia University, for example, researchers are developing computer chips that use nano-magnetic materials, which could shave up to 30% off the energy used by data centers. Advances are also being made on the research end, as illustrated by a new high efficiency research magnet being built at Florida State University that will generate a far more powerful field while using less energy. Yale’s new solder is still in the development stages but if it proves adaptable on a commercial scale, it could replace a relatively energy intensive step in the electronics manufacturing process with a simple, more energy efficient magnetic field.
Image: Solder by Garycycle2 on flickr.com.