A corrosion sensor for monitoring the early-stage environmental corrosion of A36 carbon steel

Abstract

An innovative prototype sensor containing A36 carbon steel as a capacitor was explored to monitor early-stage corrosion. The sensor detected the changes of the surface- rather than the bulk- property and morphology of A36 during corrosion. Thus it was more sensitive than the conventional electrical resistance corrosion sensors. After being soaked in an aerated 0.2M NaCl solution, the sensor's normalized electrical resistance (R/R 0) decreased continuously from 1.0 to 0.74 with the extent of corrosion. Meanwhile, the sensor's normalized capacitance (C/C 0) increased continuously from 1.0 to 1.46. X-ray diffraction result indicates that the iron rust on A36 had crystals of lepidocrocite and magnetite. © 2014 by the authors.