Optical detection of the corrosion of stainless steel 304L exposed to lithium bromide aqueous solution at 70°C

Abstract

We report a new method based on the ratio of the optical transmittance to monitoring processes of corrosion in stainless steel 304L immersed in a aqueous solution of lithium bromide at 50% wt, at 70°C. The change of the optical transmittance that is measured in the solution contaminated, is related to the physical degradation of the samples of stainless steel. We determine that the optic spectral-interval with more sensitivity to the corrosion products-accumulation, dissolved in the lithium bromide solution is of [450 nm - 750 nm]. A laser at 632 nm is utilized to detect the corrosion oxides-accumulation dissolved in the lithium bromide solution for 20 days. The slope of the change ratio of the optical power of transmittance is of 31X10-3/hour for 480 hours of exposition. Finally, the experimental results that we have presented, show that this optical technique represents an alternative in the detection of the corrosion without establishing physical contact with the sample.