Electrochemical Noise Analysis on Corrosion Behavior of Carbon Steel Covered with Mill Scale

Abstract

Corrosion diagnosis and the corrosion mechanism investigations of carbon steel covered with mill scale in distilled water and aqueous solution containing various component (Cl^-, SO₄^2-, HCO₃^-, SiO₂) were performed by using ENA. It has been clarified that the corrosion patterns could be discriminated by the measurements of potential time series and that the effects of the water quality factor on the corrosion could be discussed. Bicarbonate ions whose concentration is less than 10ppm accelerate the corrosion of carbon steel covered with mill scale. Besides, the bicarbonate ions whose concentration is 100ppm stabilize the mill scale. In neutral solution, the dissolved silica accelerates the anode reaction of carbon steel. Contrary to this in alkaline solution, the dissolved silica gives the corrosion resistance to the carbon steel with covered with mill scale.