Magnetic Particle Inspection

Magnetic Particle Inspection MPI is a NDT technique for detecting surface and subsurface discontinuity in ferromagnetic materials such as iron, nickel, cobalt and some of their alloys. We offer on-site magnetic particle inspection services using yoke type, prod type and coil type magnetizing equipment; dry powder, wet magnetic particles & wet fluorescent magnetic particle technique.


  • Most weld discontinuities open to or near the surface
  • Most suitable for cracks, laps, seams, voids, pits, subsurface holes, and other surface or slightly subsurface, discontinuities in ferromagnetic materials


  • Relatively economical and expedient
  • Test equipment is considered portable
  • Unlike liquid penetrant, magnetic particle can detect some near surface discontinuities
  • Can inspect through thin coatings


  • Application only to ferromagnetic materials as well as to surface or near-surface flaws
  • Parts should be clean before and after inspection
  • Thick coatings may mask rejectable indications
  • Some applications require parts to be demagnetized after inspection
  • Magnetic particle test requires use of electrical energy for most applications
  • Some potential for arc strikes on surface