What are characteristics of good magnetic particles used in MPT?

Good magnetic particles used in Magnetic Particle Testing (MPT) have specific characteristics that enhance the effectiveness of the method in detecting surface and near-surface defects in ferromagnetic materials. High magnetic responsiveness is crucial because it ensures that the particles will be attracted to areas of magnetic flux leakage, which is indicative of a discontinuity or flaw in the material being tested. This property enables the particles to cluster around defects, making them more visible.

Additionally, good visibility is essential for accurate inspection. Magnetic particles often come in various colors, with a preference for colors that provide high contrast against the surface of the material being inspected. This ensures that any defects are easily detectable by the inspector, facilitating rapid and effective evaluation.

Together, these characteristics—high magnetic responsiveness and good visibility—are vital for the reliability and efficiency of the MPT process. They ensure that the testing can be performed quickly and effectively, leading to accurate identification of potential issues in the tested components.