//lurk off
Non destructive testing method ??
Magnetic Particle Testing:
The Magnetic Particle Inspection method of Non-Destructive testing is a method for locating surface and sub-surface discontinuities in ferromagnetic material. It depends for its operation on the face that when the material or part under test is magnetized, discontinuities that lie in a direction generally transverse to the direction of the magnetic field, will cause a leakage field, and therefore, the presence of the discontinuity, is detected by use of finely divided ferromagnetic particles applied over the surface, some of these particles being gathered and held by the leakage field, this magnetically held collection of particles forms an outline of the discontinuity and indicates its location, size, shape and extent.
A couple of threads mentioned infi was magnetic from fault testing so I guess the above is the reason. I could be completly wrong though!
//lurk on
