What is the primary purpose of Magnetic Particle Inspection (MPI)?

The primary purpose of Magnetic Particle Inspection (MPI) is to detect surface and near-surface discontinuities in ferromagnetic materials. MPI is a non-destructive testing (NDT) method that relies on the magnetic properties of certain materials, particularly ferromagnetic ones, to identify flaws such as cracks, seams, or inclusions that may compromise the integrity of the material.

During the MPI process, the material is magnetized, and then fine magnetic particles are applied to the surface. Any discontinuities that disrupt the magnetic field will cause the particles to accumulate at these locations, making the flaws visible. This method is particularly effective for detecting surface-breaking defects and near-surface discontinuities, which is crucial in industries such as aerospace, automotive, and manufacturing where the structural integrity of components must be ensured.

The other choices do not accurately describe the primary function of MPI. Measurement of material thickness or detection of subsurface corrosion in metals falls outside the scope of MPI's capabilities, which is specifically tailored for identifying flaws on or just below the surface of ferromagnetic materials. Non-metallic materials are also not suitable for MPI, as they do not exhibit the magnetic properties required for this inspection method.