Which types of materials are primarily tested using Magnetic Particle Testing?

Magnetic Particle Testing (MPT) is specifically designed to detect surface and near-surface discontinuities in ferromagnetic materials. This method relies on the principles of magnetism; thus, it works best with materials that can become magnetized, such as iron, nickel, cobalt, and their alloys.

When a ferromagnetic material is magnetized, any flaws or defects present within the material disrupt the magnetic field, causing magnetic particles applied to the surface to accumulate at the sites of these discontinuities. This accumulation provides a visual indication of the defects, making it easier to identify potential issues within the material.

The other materials listed do not possess ferromagnetic properties, which is why they are not suitable for Magnetic Particle Testing. Non-ferromagnetic materials, composite materials, and plastics cannot be magnetized and thus do not yield the same results when subjected to this testing method. The inability to magnetize these materials prevents MPT from effectively revealing any potential flaws that may be present.