Which type of material can MPT primarily detect?

Magnetic Particle Testing (MPT) is specifically designed to detect surface and near-surface discontinuities in ferromagnetic materials. This is because MPT relies on the magnetic fields generated in these materials. When a ferromagnetic material is magnetized, any discontinuities such as cracks or voids can disrupt the magnetic field, causing particles to accumulate and form an indication at the site of the flaw.

The effectiveness of MPT is attributed to the properties of ferromagnetic materials, which can be easily magnetized and have a high magnetic permeability. This allows the method to highlight even small defects that could compromise the integrity of a component.

In contrast, non-magnetic materials, metals, and alloys that do not exhibit ferromagnetic properties will not respond suitably in MPT, as they do not allow magnetic fields to penetrate or be retained effectively. Plastic composites, being non-magnetic, also cannot be tested using MPT, as they do not have the necessary magnetic properties for this testing method. Therefore, the correct choice is that MPT primarily detects ferromagnetic materials.