IEEE—Researchers in Germany have put a thermoelectric generatorwhere no electronics have gone before: inside molten metal. The research is certain to appeal to manufacturers who hope someday to be able to plant tiny self-poweredsensors inside metal parts during casting. The sensors could also find their way into gears and bearings exposed to large mechanical loads, in nuclear reactor walls to monitor possible radioactive leakage, or in the steel structures of bridges to track deterioration. But challenges remain, among them chip sizes that can affect the structural soundness of certain metal parts.
A team of scientists from the Institute for Microsensors, Microactuators and Microsystems at the University of Bremen, in Germany, and the Fraunhofer Institute for Manufacturing Technology and Advanced Materials came up with the embedding process, which can allow the thermoelectric generators to survive a dunk in molten aluminum and perhaps magnesium, brass, and bronze. The details of the process will be reported in an upcoming issue of IEEE Electron Device Letters.
In devising the method, the researchers had to overcome two major challenges: First, extreme heat normally destroys such devices. Second, the thermal mismatch between metal and silicon causes extreme stress as the molten metal cools.
