HPAC Magazine

Capacitive imaging sensor holds promise for detecting pipe corrosion

March 20, 2012   HPAC Magazine

Researchers at NRC are investigating the use of capacitive imaging sensors for determining the extent of corrosion on metallic pipe. Detection and quantification of pitting corrosion is required to understand the condition of the pipe and its remaining service life. Capacitive imaging technology has the potential to provide a cost-effective way to acquire this information under harsh field conditions. This non-contact and non-invasive technique was applied by researchers at the University of Warwick, U.K. to non-destructive inspections of objects made of various materials. A pair of capacitive electrodes is used to generate an electrostatic field within an object. The type of material and the geometry of the object determine its dielectric properties, which in turn influence the electrostatic field. Changes in material properties due to degradation, as well as the presence of defects and cracks, can be detected by moving the electrodes over the surface of the object. The penetration depth of the electrostatic field into the material is determined by the material’s dielectric properties as well as the sensor shape, configuration and the frequency of the applied electrical field. Read more….