What property of a magnetic metal part influences the impedance of an eddy current test coil?

The impedance of an eddy current test coil is influenced by multiple properties of the magnetic metal part under inspection, and all the options mentioned play a significant role.

Conductivity is crucial because the ability of the material to conduct electrical current directly affects how eddy currents are induced and dissipated within the material. Higher conductivity typically results in stronger and more easily induced eddy currents, impacting the test coils' impedance.

Dimensions also influence impedance due to the geometric relationship of the test coil and the part being tested. The size and shape of the component can affect the distribution of the magnetic fields and the eddy currents induced. For example, larger parts may present different impedance characteristics compared to smaller parts, primarily because of how the eddy currents flow within the material.

Permeability is another critical factor as it describes how well the material can support a magnetic field. Higher permeability allows for more efficient magnetic coupling between the test coil and the material, which can significantly affect the inductance and, consequently, the impedance of the coil itself. Materials with higher permeability can cause eddy currents to be more concentrated, changing the impedance readings.

Therefore, considering the influence of conductivity, dimensions, and permeability collectively, it is accurate to conclude that all of these properties impact