MPI is a non-destructive testing (NDT) process for detecting surface and slightly subsurface discontinuities in ferroelectric materials such as iron, nickel, cobalt and some of their alloys. The process puts a magnetic field into the test object. When the part is magnetized, flaws perpendicular to the magnetic field direction cause flux leakage. If a lapse or a crack is present the magnetic particles will be attracted to the flawed area, providing our technician with what is called an indication. Our technician will then evaluate the indication to assess the location, size, shape and extent of these imperfections.