Title :
SQUID NDE: detection of surface flaws by magnetic decoration
Author :
Thomas, I.M. ; Ma, Y.P. ; Wikswo, J.P., Jr.
Author_Institution :
Dept. of Phys. & Astron., Vanderbilt Univ., Nashville, TN, USA
fDate :
3/1/1993 12:00:00 AM
Abstract :
A nondestructive evaluation (NDE) surface-flaw detection technique involving decoration of the samples with a ferromagnetic or paramagnetic tracer and subsequent scanning with a high-resolution magnetometer or susceptometer is considered. The authors present the results of a preliminary study demonstrating that this technique is sensitive enough to detect and image defects at least as small as 254 mu m*51 mu m*76 mu m deep in a nickel-alloy test block. Applied field strength and superconducting quantum interference device (SQUID) noise limit sensitivity, and sensing coil characteristics limit spatial resolution.<>
Keywords :
SQUIDs; flaw detection; magnetic field measurement; magnetometers; nickel alloys; Ni alloy test block; SQUID NDE; SQUID noise; applied field strength; ferromagnetic tracer; high-resolution magnetometer; magnetic decoration; nondestructive evaluation; paramagnetic tracer; scanning; sensing coil characteristics; sensitivity; spatial resolution; superconducting quantum interference device; surface-flaw detection; susceptometer; Interference; Magnetic susceptibility; Paramagnetic materials; SQUID magnetometers; Spatial resolution; Superconducting coils; Superconducting device noise; Superconducting devices; Superconducting magnets; Testing;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
