What is magnetic particle inspection?

Magnetic Particle Inspection (MPI) is a non-destructive testing method used to detect surface and slightly subsurface discontinuities in ferromagnetic materials such as iron, nickel, and cobalt. The process involves magnetizing the material and then applying ferrous particles over the surface. If there are any cracks or defects, the magnetic field is disrupted, causing the particles to gather at the site of the flaw, making it visible under proper lighting conditions. MPI is widely used in industries like aerospace, automotive, and manufacturing for quality control and safety assurance.