Magnetic Particle (MPI) is one of the most widely utilized non-destructive testing techniques. This technique is primarily used to find surface breaking discontinuities and some subsurface discontinuities.
Magnetic Particle Inspection of ferromagnetic materials relies heavily on the laws of magnetism possibly first introduced by Aristotle in the mid 300’s BC. Using magnetic fields, small ferromagnetic particles are attracted to leakage fields (defects) and are visible at the accumulation site.