In 1861, Hans Goldschmidt found a simple way to produce and use very high temperatures by mixing aluminum with a metallic oxide. The process is used in welding. Today, scientists working at the nano-scale are designing similar techniques in which a filler metal is melted to join metal pieces together.
Chemists can craft a menagerie of metallic nanoscale objects, but building those bits into working devices is tricky. Now, Beverley Inkson, Yong Peng, and Tony Cullis of Sheffield University, in England, have developed one way to do it by welding nanowires together via a nanoscale soldering technique. Simply bringing nanoobjects into contact with one another doesn’t ensure reliable, long-lasting bonds that are required for practical devices. Researchers previously developed a number of ways to connect nanoscale objects, but these approaches aren’t yet practical for industrial applications. The new technique is much like macroscale soldering in which a filler metal is melted to join metal pieces together. Instead of a soldering iron, the Sheffield team uses the manipulators of a scanning electron microscope to place a piece of sacrificial metal nanowire where the nanoobjects are to be joined. They then apply an electric current, which welds the assembly together. The technique can fuse objects as small as 10 nm and could be used to fabricate nanosensors and nanoelectronics.
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Excerpted with permission, Chemical & Engineering News
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