Oxidation behaviour of Sodium and Potassium choride coated Fe-C alloy at 400-700°C

Abstract

The studies have been conducted on the oxidation behaviour of Fe-C alloy at 400 to 700 °C in presence of alkali metal chloride salts such as sodium chloride and potassium chloride. The chloride compounds decompose at high temperature, resulting the formation of sodium oxide and chlorine gas, which enters the scales and causes accelerated oxidation attack. This leads to break the protectivity of the alloy surface, developing the cracks and porous scales. The studies were carried out for the periods of 120 h in air. The temperature is directly proportional to the corrosion rate, the curves followed the parabolic behaviour. The alkali metal salts have deleterious effect on the alloy. The investigation tests include the oxidation kinetics, the scale morphologies were determined by using Optical Microscopic techniques.