SQUIDS (super conducting quantum interference devices) are ultra sensitive magnetic field detectors that are used in many devices including the machine meant for brain scanning. They can now be used to detect corrosion in metals. When a metal corrodes, tiny currents are created inside the metal because of the movement of charged particles. These currents, in turn, produce a small magnetic field which the SQUIDS are sensitive enough to measure. Airplane engineers will be able to check out the rivets and other parts for corrosion without actually removing them.