Magnetic particle inspection (MPI) is a nondestructive testing method
used for defect detection. MPI is fast and relatively easy to apply,
and part surface preparation is not as critical as it is for some other
NDT methods. These characteristics make MPI one of the most widely
utilized nondestructive testing methods.
MPI uses magnetic fields and small magnetic particles (i.e.iron filings) to detect flaws in components. The only requirement from an inspectability standpoint is that the component being inspected must be made of a ferromagnetic material such as iron, nickel, cobalt, or some of their alloys. Ferromagnetic materials are materials that can be magnetized to a level that will allow the inspection to be effective.