In eddy current testing, which condition may lead to inaccurate results?

In eddy current testing, the presence of coatings can significantly impact the accuracy of the results. Eddy current testing relies on the measurement of electrical currents induced in conductive materials. When coatings or insulation are present on the surface of the material being tested, they can interfere with the flow of the induced currents. This results in a reduction of sensitivity to flaws within the substrate material, leading to potentially missed defects or incorrect readings regarding material thickness or electrical conductivity.

In contrast, a low test frequency can affect sensitivity but does not inherently undermine accuracy in the same way that coatings do. A uniform test surface is generally desirable, as it allows for consistent measurements. Constant temperature helps maintain stability in the electrical properties of the materials being tested, which is also beneficial for accurate results. Thus, the presence of coatings is indeed a condition that can lead to inaccuracies in eddy current testing outcomes.