Evaluation of the Corrosion Rate for Acidic Bottom Plates of an Aboveground Oil Tank by the AE Method

Abstract

An AE method is an effective technique that can inspect corrosion damage of tank bottom plates to prevent leakage accidents of oil storage tanks. However, a correlation between AE signals and the corrosion behavior for bottom plates is not fully clarified. In this study, the authors considered that the corrosion regions in bottom plates become a strong acid environment by chloride ions as shown our previous work. The correlation between the AE signals and the corrosion behavior with a potentiostat for test pieces was examined in the environment. The polarization resistance was measured with an AC impedance method using a frequency response analyzer. It was clear that the polarization resistance indicated the corrosion rate for a test pieces in the experiments. While measuring the AE signals, the corrosion rate was monitored with a test piece. As a result, the AE signal showed the good correlation with the corrosion rates of the test pieces.