Magnetic Particle Inspection
Magnetic particle inspection (MPI) is a nondestructive testing method used for surface and sub-surface 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 to detect flaws in components. The only requirement is that the component being inspected must be made of a ferromagnetic material such as iron, nickel, cobalt, or some of their alloys.