When selecting magnetic particles, what parameters should be considered?

The selection of magnetic particles for Magnetic Particle Inspection (MPI) is crucial for effective flaw detection, and size, shape, and magnetic characteristics are fundamental parameters to consider.

Size plays a significant role because smaller particles can penetrate finer cracks and surface discontinuities, enhancing the sensitivity of the inspection method. If the particles are too large, they may not adequately reveal the presence of defects in tight or narrow spaces.

The shape of the particles also affects their behavior during the inspection process. Irregularly shaped particles tend to cling to the magnetized areas more effectively than spherical particles, increasing their retention in areas where defects are present. This characteristic improves the likelihood of producing visible indications of flaws.

Magnetic characteristics are essential to ensure that the particles respond effectively to the magnetic field. Particles must possess sufficient magnetic permeability to become magnetized in the presence of a magnetic field but should also have the appropriate residual magnetism to stay in place and form indications where the magnetic field is disrupted by a flaw.

While factors such as cost, availability, uniformity, and residual magnetism may be relevant to the overall process or practical aspects of using magnetic particles, they do not directly influence the effectiveness of flaw detection like size, shape, and magnetic characteristics do. Therefore, focusing