Estimation of Corrosion of Metals Using Fiber Optic Displacement Sensor System

A new approach to probe the surface roughness of mild steel due to atmospheric corrosion using a fiber optic sensor system is described. The scattering principle is used to estimate the average surface roughness that is observed between 2.85 µm and 5.40 µm for the corroded surface and 0.11 µm and 0.16 µm for the polished surface respectively. The maximum sensitive region is estimated below the 0.10 mm for the polished surface. Specular and diffuse reflection is measured at normal incidence of fiber. Reflected intensity of corroded surface can be used to estimate the roughness, Ra. The rate of corrosion is determined by weight loss measurement technique and it is found to be linear with measured average roughness, Ra. This work suggests the possibility of using average surface roughness, Ra of atmospheric corroded mild steel to predict the approximated value of rate of corrosion.