What does the magnetic particle method reveal?

The magnetic particle method is a non-destructive testing technique primarily used to detect surface and near-surface discontinuities in ferromagnetic materials. This method involves the application of magnetic particles, either dry or in a liquid suspension, to the surface of the material being tested. When an external magnetic field is applied, the magnetic particles will congregate at areas where there are discontinuities, such as cracks or other defects, revealing surface flaws effectively.

This technique is widely used because it is relatively quick, cost-effective, and provides immediate results, making it particularly useful in industries where the integrity of materials is crucial, such as in manufacturing, automotive, and aerospace sectors.

The other options do not accurately describe the primary capability of the magnetic particle method. For instance, while internal stresses can affect the performance of a material, the magnetic particle method focuses on surface defects and does not evaluate internal stresses directly. Similar reasoning applies to the overall material quality and resistance to magnetic fields, as these aspects are outside the purview of what this specific testing method reveals.