Characterization of Fiber Optic Sensor for Corrosion Monitoring

This work was conducted to find the parameter that can be used to determine the stages of corrosion of metals. Samples of iron copper and aluminum with unclad optical fiber strapped onto each of them were soaked in corrosive solution. The corrosion process is monitored by a spectrometer linked to a computer. Direct intensity transmission spectrum and reflection spectrum profiles are displayed on the computer. Reflection spectrum is produced using a fiber Y-probe. The intensity profiles obtained from both of the methods are the characteristic profiles of the light source used.Two distinct characteristic peaks of the white LED are observed in the profile. The fluctuation in the intensity of the transmitted light is thought to be due to the electrochemical reaction taking place in each metal as the corrosion activity is taking place whereas the fluctuations in the reflected spectrum are due to the different colour of the corrosion product produced with exposure. Thus the change in the intensity from both types of the spectrum cannot be used as a measure of the stages of the corrosion activity of the metals.