Electrode for measuring ohmic and impedance characteristics of protective coatings of pipelines

We propose a mobile electrode of original design for measuring the ohmic and impedance characteristics of protective coatings on pipes of diameter 57 to 1420 mm under laboratory and field conditions. The electrode was calibrated on plane specimens with respect to measurements of the transient ohmic resistance by the method of "hollow cylinders." We present the results of measurements of the transient ohmic resistance of identical coatings on plane specimens and pipes of different diameters as well as the values of relative errors. A good agreement between the results of investigations is shown. Owing to the original design of the working chamber and magnetospring hold-down device, the electrode can be used for the survey of inclined, wall, and ceiling surfaces of steel structures. As a result, we conclude that it is expedient to introduce this electrode into the State Standard.