1992 Volume 41 Issue 12 Pages 803-808
Corrosion deterioration of steel structures has been serious problems. It is important not only to detect average corrosion rate but also to observe surface texture of corroded steel, because pitting or localized corrosion gives a large damage to the structure. FFT algorithm was used for characterization of the surface texture. Mild steel plates, 10×10cm2, which were exposed in several places in marine environment for one year were examined. Surface textures of the sample plates were observed by surface roughness meter which was detected electromagnetic induction current. It was found that parameter CFFT which was derived from FFT analysis was related to an amount of corrosion, and was also found that autocorrelation function, which was calculated from FFT result, suggested the distance from anodic area to cathodic area. The corrosion mechanism of mild steel in marine environment was discussed from these results.