Which frequency provides the greatest eddy current penetration in aluminum?

The frequency that provides the greatest eddy current penetration in aluminum is the lowest frequency option, which is 300 Hz. Eddy currents are induced in conductive materials by alternating magnetic fields, and the penetration depth is influenced by the frequency of the current.

Lower frequencies create longer wavelengths, which allow the electromagnetic fields to penetrate deeper into the material. In the case of aluminum, using a frequency of 300 Hz results in higher penetration compared to higher frequencies such as 1 kHz, 3 kHz, and 10 kHz.

At higher frequencies, the eddy currents tend to remain closer to the surface of the material due to the skin effect, which limits their depth of penetration. This characteristic is significant for non-destructive testing, as it enables inspectors to assess thickness and detect flaws within the material. Therefore, for applications requiring deeper penetration into aluminum, lower frequencies are preferred.