Hot Corrosion Behaviour of Aluminide and Rare-earth Oxide Containing Aluminide Coating on Mild Steel

摘要

Aluminide and rare-earth oxide containing aluminide coatings on mild steel have been prepared by pack-cementation process. The hot corrosion behaviour of coated and uncoated alloy has been studied at 700, 800 and 900 deg C under a limited supply of air. The study involves measurements of weight gain vs time and weight gain vs amount of Na_2SO_4 deposited measurements. The performance of coatings have been studied by measuring oxidation kinetics, metallography, SEM and X-ray diffraction analysis techniques. In Na_2SO_4 induced hot corrosion of aluminide coatings, formation of sodium metal oxide and metal sulfide is shown depending upon the oxygen activity around the salt/scale or scale/alloy interface.