A PCB Sensor for Detecting Ferrous Corrosion Products in Sand

Corrosion is a serious problem that is exacerbated by exposure to salty air or saltwater in coastal regions. In these locations, rust flaking from iron and steel structures will accumulate in the sand beneath them. Detection of these ferrous corrosion products in the sand is useful for the early detection of corrosion. To accomplish this goal, a low-cost planar inductive sensor was fabricated in printed circuit board sensor technology for use in dry quartzarenite/calcium-carbonate-derived beach sand. The sensor was evaluated in various corrosion products and demonstrated an increase in inductance of 0.46% in pure ferric oxide, 9.86% in natural rust, and 103.3% in decomposed steel wool. When the sensor was evaluated in a mixture of sand and pure ferric oxide, it demonstrated a 0.1 nH increase in inductance per percent increase in the volumetric concentration of ferric oxide. Extrapolating the sensor's response to natural rust and decomposed steel wool yielded sensitivities of 3.2 nH and 33.7 nH per % increase in the volumetric concentration, respectively. This low-cost sensor will facilitate ferrous corrosion product detection in low concentrations.