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Canada helping aerospace industry go lead-free

A Canadian-led research effort is first out of the gate with innovative solutions that will enable global suppliers and manufacturers to meet new environmental standards without sacrificing reliability.

Lead has been used as an additive in soldering electronics processes for more than 50 years, but current environmental and health concerns have prompted more countries to ban its use in electronic assemblies. As a result, most consumer electronics are now lead-free, driven largely by regulations such as the European Union’s Restriction of Hazardous Substances (RoHS) directive. Those same rules require the aerospace and defense industries to comply by 2019.

A global movement away from using lead in electronics manufacturing is driving suppliers to seek alternative soldering alloys that not only meet quality and safety requirements but address regulatory compliance. Tin-based solder alloys have been the go-to alternative for several years in most consumer products but they present performance challenges for high-reliability applications.

Canada is building on over a decade of research to address these challenges through three projects jointly funded by the Refined Manufacturing Acceleration Process (ReMAP), a Business-Led Network of Centres of Excellence, and industry partners who will be among the first to benefit from the technologies. The industry partners represent all segments of the value chain: Celestica, an electronics manufacturing supplier; component manufacturers Honeywell, Rockwell Collins and Curtis-Wright; and systems integrator BAE Systems.

With researchers from the University of Toronto, the team developed new tin-based solder alloys that can be manufactured at a lower temperature and don’t rely on lead. The lower-melting characteristics of these alloys are what make them unique.

These patent-pending Canadian technologies have several advantages over other tin-based solder alloys. They minimize the risk of tin whiskers, which can short-circuit electronics; they behave similar to leaded alloys enabling the use of traditional manufacturing processes; and solder joints can be reconditioned to time zero even after a long operational life or storage in the field (20+ years).

“ReMAP has enabled further development of the research to bridge the commercialization gap,” says Irene Sterian, Executive Director, ReMAP.

Several industry consortia are testing the new lower temperature alloys, aimed to be commercially available in time to meet the European Union’s 2019 lead-free deadline. Any company exporting to the EU is required to follow the new legislation.

“These alloys can be used for aerospace, military or any other sector that requires high reliability. Canada has been a pioneer in this field and now several international consortia are investigating the alloys for global adoption, including AREA Consortia, HdPug, iNEMI, CALCE and NASA,” says Polina Snugovsky, the Principal Engineer and Chief Metallurgist of Global Technology and Innovation at Celestica, ReMAP’s lead industry partner.

One the main benefits of the new alloys is their ability to mitigate tin whisker growth for mission critical applications including aerospace, defence and medical devices. In 2005 the Millstone nuclear generating plant in Connecticut shut down when a circuit board monitoring a steam pressure line short-circuited. Tin whiskers—microscopic growths of metal from soldering points in a circuit board—were the cause. The US military attributed these same growths to malfunctioning F-15 radar systems and misguided Phoenix and Patriot missiles.

“This has been a very difficult problem for the industry to solve, and we’ve proposed a solution with the most promising results,” says Dr. Snugovsky, one of the lead researchers on the three ReMAP projects developing and testing the new alloys and processes.

“Electronics for an aircraft or in military equipment begin to deteriorate after 10 or 20 years. We came up with a specialized treatment that can return the metallurgic properties of the alloy to time zero, putting it back to its original properties.”

“Complying with the European Union’s RoHS directive is an important industrial priority for Celestica,” says, Jeffrey Kennedy, Celestica’s Technology Director. “The support Celestica and our project partners have received from ReMAP has accelerated the development of new lower temperature alloys that are designed to meet the aerospace industry’s high performance reliability standards. It has put Canada at the leading edge of this exciting field of materials innovation.”

Sterian says medical device manufacturers can also use these unique materials and processes for future production runs, “because the materials they’ve used in the past will no longer be available. This is an example of lateral innovation. Pioneering technologies in assembly and distribution can be leveraged in healthcare applications that also require high-reliability.”

To read more about lead-free solders, see This link will take you to another Web site “Green Manufacturing for High Reliability Electronics: ReMAP New Lead-Free Solders.”