Practice session

a. Define corrosion and explain the difference between dry and wet corrosion. (3 marks)

b. What is differential aeration corrosion? Illustrate with a diagram. (3 marks)

c. A piece of corroded steel plate was found in a submerged ocean vessel. It was estimated that the original area of the plate was 10 inch² and that approximately 2.6 kg had corroded away during the submersion. Assuming a CPR of 200 mpy for this alloy in seawater, estimate the time of submersion in years. The density of steel is 7.9 g/cm³. [Given K = 534] (4 marks)