What happens to the sensitivity of eddy current testing as the conductivity of the specimen decreases?

As the conductivity of the specimen decreases, the sensitivity of eddy current testing also decreases. This is primarily due to the principles governing how eddy currents are generated and how they interact with conductive materials.

When a conductor has high conductivity, it supports the generation of stronger eddy currents in response to the test signal. These strong eddy currents create more significant variations in the electromagnetic field, which results in a more pronounced response in the measurement equipment. Conversely, when the conductivity is lower, the magnitude of the generated eddy currents is reduced. This diminishes the strength of the resultant signal and makes it more difficult to detect smaller flaws or irregularities in the material. As a result, the overall sensitivity of the testing method is compromised.

Consequently, understanding the relationship between conductivity and sensitivity is crucial for effective eddy current testing, as it impacts the ability to accurately assess the integrity of materials and detect potential defects.