Investigation of Hot Corrosion Behaviour of Uncoated and WC-17CO Coated Samples in Aggressive Molten Salt Environment

Hot corrosion is usually a significant issue in powe r plant’s boilers. The alloys and metals get corrod ed, once exposed to high temperature corrosion in air, or in actual boiler environment in power plants. In order to protect materials; thermal spraying is a newly developed tec hnology that enhances high temperature corrosion re sistance of boiler steels. In the present study, WC-17Co coatin g were deposited by HVOF technique on substrate ASTM-SA 213-T91. Subsequently; high temperature corrosion behavior o f uncoated and WC-17Co coated substrate T91 was inve stigated in molten salt environment at an elevated temperature of 9000C for 50 cycles. The experimental cyclic study consi sted a cycle of 1 hour heating of samples in SiC tube furna ce, followed by 20 minutes of cooling in room tempe rature. Surface morphologies of corroded samples were carried out by SEM/EDS and XRD analysis. In the results, bare materi al s corroded with intense peeling and spalling. But on th e other side, WC-17Co coating performed better than the uncoated steel substrate.