TO STUDY THE HIGH TEMPERATURE CORROSION BEHAVIOUR OF D-GUN SPRAYED STELLITE-6 COATING IN SIMULATED BOILER ENVIRONMENT

Abstract

Hot corrosion problem frequently encountered in oil-fired boilers due to the presence of vanadium and sodium. Steels are widely used in boilers to construct the super heater tubes, which are used at high temperature area. To obviate the problem of corrosion in such area, studies have been done on 347H steel, which is widely used to construct the super heater tubes. To simulate the boiler environment, 60% Na2SO4-40% V205 salt has been applied on the substrate and exposed at 900°C for 100 cycles. Weight gain measurements have been taken to monitor the corrosion kinetics. Characterization of corrosion products has been done using FESEM/EDS and XRD and Cross -sectional/ mapping analysis. D-gun sprayed satellite-6 coating has contributed to increase in the oxidation resistance of coated super alloy.