Success Story

Touching the Lives of Billions Worldwide: Lead Free Solder

A lead free solder, developed at Ames Laboratory by Iver Anderson, John Smith, Chad Miller, and Robert Terpstra with a co-inventor, Frederick Yost, at Sandia National Laboratory, combines tin, silver and copper in a novel alloy combination that is low melting, applies easily on typical metal joints, and has a reasonable cost, serving as a direct (no-cost) swap in the industrial setting. This revolutionary solder alloy replaces many uses of the traditional tin-lead, low-melting solder, reducing further the number of lead toxicity hazards in our everyday environment.

The use of leaded solder has a 5000-year history. There are examples of its use in Mycenae from about 1500-1300 BC, during the Roman Empire and in Denmark around 800AD. Modern electronic assembly uses solder to attach electronic chips and components to printed wiring boards to create an electronic assembly which are joined to form functional systems like cellular phones, computers or televisions. The Ames Laboratory solder alloy formula is now considered a preferred leadfree solder by the worldwide electronics assembly industry and can be found in many new consumer electronic items, including cell phones, laptops, TVs, and VCRs.

The technology’s initial two patents, (5,527,628 and 6,231,691) were licensed to a small business, Johnson Manufacturing, Princeton, IA. To extend the availability of the solder, two other licensees, Multicore Solders of Richardson, Texas (now Henkel Corporation), and Nihon Superior Co. Ltd. of Osaka Japan, also obtained licenses to the technology. A Japanese industry-based consortium set up a voluntary initiative to go lead-free in consumer electronics beginning in 2000, spurring a widespread movement in this direction. Subsequent legislation enacted by the European Union to eliminate most of the lead in consumer goods sold in Europe by July of 2006 resulted in more broad licensing interest. As a result, the technology was sublicensed to over 65 companies worldwide. The initial patent expired in July 2013.

Federal funding through the Department of Energy was provided for the basic research and technology development of the solder. DOE funding developed the metal and alloy powder production capability, the eutectic tin-silver-copper composition, joint microstructure and properties studies, and alloy additions for resistance to thermal aging. The Laboratory’s Contractor, Iowa State University Research Foundation, and Nihon Superior provided development funds. Ongoing product development continues to try to improve drop impact strength, thermal aging, and thermal fatigue resistance; two patent applications on improvements were filed with the US Patent and Trademark Office in 2010 and 2013.