What does an "impedance plane" diagram represent in Eddy Current Testing?

An impedance plane diagram is a valuable tool used in Eddy Current Testing (ECT) to visualize the relationship between resistance and reactance in a tested material. This diagram allows technicians to interpret the impedance characteristics of a given metallic component when subjected to an alternating electromagnetic field. The horizontal axis typically represents the resistance, while the vertical axis represents the reactance.

By analyzing the placement of test data points on this diagram, inspectors can identify variations in material properties and potential defects. Distinct defects will cause noticeable shifts in the measured impedance, making it easier to differentiate between acceptable and defective components based on their impedance response. This relationship is crucial for understanding the conductivity and permeability of the material being tested, which directly correlates to its structural integrity.

In the context of ECT, this option reflects the foundational principles that govern the technique, making it the correct choice in this question. Other options, while related to testing processes or outcomes, do not specifically address the significance of the impedance plane diagram in the way that the relationship between resistance and reactance does.