Hot corrosion behaviour of CNT-reinforced zirconium yttrium composite coating at elevated temperature

• Published in: Materials today : proceedings Vol. 28; pp. 1530 - 1539
• Main Authors: Kumar, Sandeep, Bhatia, Rakesh, Singh, Hazoor
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2020
• Subjects: Air plasma spray; Boiler tube steel; Carbon nanotubes; Hot corrosion; Carbon nanotubes; Boiler tube steel; Hot corrosion; Air plasma spray
• ISSN: 2214-7853; 2214-7853
• DOI: 10.1016/j.matpr.2020.04.836

Present research work is focused on the hot corrosion resistance of plasma sprayed carbon nanotubes (CNT) reinforced with zirconium yttrium (ZrO2-Y2O3) composite coated ASTM SA-213T91 steel at 750 °C temperature in a simulated environment of molten salt. After the exposure the corrosion kinetics was examined by mass gain analysis. The corroded specimens were critically analyzed by XRD, SEM/EDAX and cross-sectional elemental technique. Investigation concludes that CNT-reinforced ZrO2-Y2O3 composite coating provides better corrosion resistance even at elevated temperature than the conventional and un-coated specimens. With the formation of protective oxide layer the composite coatings gain low weight which instead prevents the steel specimens from hot corrosion. As the content of CNT increases in the coating matrix there was improvement observed in the hot corrosion resistance. The porosity of composite coating also reduces with the addition of CNT in zirconium yttrium coating by filling voids which resulted in interlocking of corroded particles to get penetrated hence the enhancement in hot corrosion resistance.