Lead-free solder: a revolutionary solder alloy

Lead-free solder: a revolutionary solder alloy

Dr. Iver Anderson and his team at Ames Laboratory developed a new metal for soft-soldering that 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. 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.

Of several lead-free alternatives, the Ames solder alloy formula is now considered a preferred lead-free solder by the worldwide electronics assembly industry, and can be found in many new consumer electronic items, including cell phones, TVs, and VCRs. Long a proponent of technology transfer, Dr. Anderson worked directly with all three of the original licensees of the technology: Johnson Manufacturing of Princeton, Iowa; LoctiteMulticore Solders of Richardson, Texas and Great Britain; and Nihon-Superior of Japan to find new uses and make improvements.

A subsequent sublicensing agreement greatly expanded the number of licensees to well over 60 worldwide, and gave industry and consumers an easy-to-use lead-free solder for many common uses. The rapid commercialization of this lead-free solder has helped reduce the amount of lead used in manufacturing electronics and other consumer goods, and has brought profits and jobs to the licensees and significant royalty income to Iowa State University and Ames Laboratory.

Ever since discovery of the tin-silver-copper solder, Dr. Anderson’s group has worked to develop modifications to this base to improve the performance, ease of use, and durability. A subsequent patent was granted for additions, e.g., iron, cobalt, and other similar elements, to permit higher temperature applications of the solder.

Most recently, the group has worked with Nihon-Superior support to pursue other solder alloy modifications, e.g., zinc, manganese and aluminum, that can give the tin-silver-copper solder joints enhanced impact resistance as well as high temperature tolerance. In fact, a manganese addition to a particular tin-silver-copper formulation also was found to reduce further the solder alloy melting point, and a patent application has been filed for this improvement. Such manufacturing improvements and higher performance can expand the range of possible consumer applications, for example, more rugged electronic sensors and control assemblies for SUVs and cars.

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