Evaluation of the behavior of shrouded plasma spray coatings in the platen superheater of coal-fired boilers

Abstract

Nickel-and cobalt-based coatings were formulated by ashrouded plasma spray process on boiler tube steels, namely,ASTM-SA210-grade A1 (GrA1), ASTM-SA213-T-11 (T11),and ASTM-SA213-T-22 (T22). The Ni-22Cr-10Al-1Y alloy powderw as sprayed as ab ond in each case before the final coating.The degradation behavior of the baredand coated steels was studied in the platen superheater of the coal-fired boiler.T he samples werei nserted through the soot blower dummy points with the help of stainless steel wires.T he coatingsw ere found to be effective in increasing resistancet o degradation in the given boiler environment. The maximum protection was observed in the case of Stellite-6 (St-6) coating.

High-Temperature Erosion-Corrosion Performance of High-Velocity Oxy-Fuel Sprayed Ni-20 Cr Coating in Actual Boiler Environment

“…High-temperature E-C behavior of Ni-Cr coatings for Cr-Mo/ stainless steels under simulated laboratory conditions was reported by many investigators; [9][10][11][12][13][14] however, information regarding the E-C performance of Ni-20Cr coatings in actual industrial conditions is only limited. Sidhu and Prakash [15] studied the E-C performance of a plasma sprayed Ni-20Cr coating in an actual boiler environment. They observed the presence of a continuous chromium-rich layer at the scale substrate interface, which was suggested to contribute to a better corrosion resistance to the Ni-20Cr coated steel.…”

Multi-Walled CNT Reinforcement to Thermal Spray Coatings

“…Due to failure of components, the plants face closure and reduction in efficiency. Billions of dollars are spent every year for the replenishment of corroded parts, machines and equipment [10]. The sudden failure of components can lead to human injury and loss of life.…”

Corrosion Behaviour of HVOF Sprayed Coatings on ASME SA213 T22 Boiler Steel in an Actual Boiler Environment

“…Prakash [10] experimentally investigated the erosion-corrosion of plasma as sprayed and laser remelted stellite-6 coatings on boiler tube steels and It was found that coated and laser remelted T11 has high erosion -corrosion resistance. B.S.Sidhu and S. Prakash [11] applied NiCrAlY, Ni-20Cr, stellite-6 and Ni 3 Al coatings on three boiler tube steels ASTM-SA210 grade A1, ASTM-SA213-T-11 and ASTM-SA213-T-22 using shrouded plasma spray and it was notices that among all applied coatings, stellite-6 was reported to be highly protective. Bala et al [12]used two boiler steels namely SA-213-T22 and SA516 (Grade 70) to deposit Ni-50Cr powder using cold spray technique in Na 2 SO 4 -60%V 2 O 5 environment at 900°C and it was concluded that cold sprayed Ni-50Cr coating was counted to be effective in protecting T22 and SA516 boiler steels against hot corrosion.…”