Faculty Publications
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Item Microstructural Characterization and Hot Corrosion Behavior of Plasma-Sprayed Fe17Cr2Ni0.18C/Fly Ash Cenosphere-Based Composite Coating(SAE International, 2021) Hanumanthlal, S.; Siddaraju, C.; Ramesh, M.R.; Thirtha Prasada, H.P.; Somasunder, B.; Virupakshappa, L.The current investigation studies the microstructure and high-temperature hot corrosion behavior of plasma-sprayed coatings. The composition of Fe17Cr2Ni0.18C and fly ash cenosphere powder is maintained in the 0%, 5%, 10%, and 15% ratio by weight percent, respectively. Both powder mixtures were thoroughly blended correspondingly and coated on T22 boiler steel tubings. Thermocyclic hot corrosion studies were examined in a liquid salt condition of Na2SO4 - 60% V2O5 for 17 cycles of 51 h at 600°C on bare and coated steels. Thermogravimetric practice was used to establish the kinetics of hot corrosion of uncoated and coated steels. As-coated samples are studied for microstructure and microhardness. X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy-dispersive spectroscopy, and X-ray mapping characterization techniques have been utilized for structural analysis of the as-coated and hot-corroded samples. It was observed that FeCrNiC/cenosphere-coated steels showed better hot corrosion resistance than the uncoated steels. The coated steels follow the parabolic rate law of oxidation, and parabolic rate constant values are lower in comparison to the uncoated steels. Better resistance is provided by the high-temperature permanence of mullite, alumina, and defensive oxide layer of silicon that is formed at elevated temperatures. ©Item Hot corrosion behavior of plasma sprayed FeCrNiC and FeCrNiC/Cenosphere coatings on ASTM-SA213-T22 steel(Elsevier Ltd, 2022) Hanumanthlal, S.; Siddaraju, C.; Ramesh, M.R.; Thirtha Prasada, H.P.; Somasundaram, B.The steel alloys tubes used to manufacture boilers which are used in high temperature environment in thermal power plants are often subjected to high temperature corrosion. Therefore, to protect the surface of boiler tubes, protective coatings are used to counter the corrosion. In this work FeCrNiC and FeCrNiC/Cenosphere coatings deposited on T22 boiler tube steel using atmospheric plasma spraying. Thermocyclic hot corrosion studies were examined in a liquid salt condition of Na2SO4-60%V2O5 for 17 cycles of 51 h at 600 °C on uncoated and coated steel. Thermogravimetric practice was utilized to build up the kinetics of hot corrosion of uncoated and coated steel. As-coated samples are studied for microstructure and microhardness. The X-ray diffraction(XRD), Scanning electron microscopy(SEM)/Energy dispersive spectroscopy(EDX), and X-ray mapping characterization techniques were used to analyse the corrosion products. It was observed that FeCrNiC/Cenosphere coated steel showed better hot corrosion resistance than the uncoated steels. Parabolic rate constant values of coated steel are lower in comparison to the uncoated steels. Better resistance is provided by high-temperature stability of mullite, alumina, defensive glassy oxide layer of silicon, titanium and spinels of chromium and carbon that is formed at elevated temperatures. © 2021