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Planes, trains, automobiles, bridges, and pipelines all have one thing in common: corrosion. To the tune of $300 billion a year, rust and rot are gnawing away at America's infrastructure. What's worse, only a third of the damage is detectable by current means.
Enter the superconducting quantum interference device (SQUID), a transducer used to detect extremely small magnetic fields. A new variant of the SQUID, developed at Vanderbilt University by John P. Wikswo Jr. and R. Grant Skennerton, can detect minute amounts of corrosion, even when buried deep inside a metal object. The SQUID is a magnetometer so sensitive that it can easily sniff out the minute changes in magnetic fields that occur when metal oxidizes. "Other than the SQUID, there are no other techniques that can give information about the instantaneous rate of corrosion," Wikswo says.
While the system is currently confined to a lab, where confounding factors such as the earth's magnetic field can be screened out, SQUID is still useful for studying the conditions under which metal parts are prone to rust. The Air Force will be the first to use Vanderbilt's SQUID technology to measure rates of hidden corrosion activity in fuselage joints. A commercial version of the device could be available in two years. By Petty Fong EDITED BY Edited by Adam Aston