Ramesh, M.R.Medabalimi, S.Rupanagudi, R.S.Prasad, C.D.Sollapur, S.B.2026-02-042024JOM, 2024, 76, 6, pp. 3172-318410474838https://doi.org/10.1007/s11837-024-06526-1https://idr.nitk.ac.in/handle/123456789/21095At high temperatures, coatings provide a protective scale development on surfaces to maintain long-term stability. In the current study, ASTM-SA210-Grade A1 (GrA1) and ASTM-SA213-T-11 (T11) boiler tube steels were coated with NiCrAl alloy with high-velocity oxy-fuel (HVOF) to prevent oxidation and hot corrosion. For hot corrosion and oxidation, 50 cycles at 900°C were taken into account. Additionally, tests of hot-corrosion behavior were conducted in an atmosphere containing molten salt (Na<inf>2</inf>SO<inf>4</inf>-60%V<inf>2</inf>O<inf>5</inf>), while tests of oxidation behavior were conducted in static air. The kinetics of oxidation were calculated using the thermogravimetric method. Using XRD, EPMA, and SEM/EDAX methods, the produced oxide scales were characterized. The oxidation rate of NiCrAl-coated steels was found to be lower than that of uncoated steels. The coated steels subjected to oxidation in air exhibit slow scale growth kinetics and oxides of α-Al<inf>2</inf>O<inf>3</inf> and Cr<inf>2</inf>O<inf>3</inf> on the outermost surface, while accelerated oxidation caused by the molten salt exhibits metastable Al<inf>2</inf>O<inf>3</inf>. Along the nickel-rich splat boundary, Cr and Al were formed a preferential oxidation, which prevents other oxygen from entering the coating via pores and voids, resulting in steady-state oxidation. © The Minerals, Metals & Materials Society 2024.AluminaAluminum alloysAluminum coatingsAluminum corrosionAtmospheric corrosionBoiler corrosionBoilersChromium alloysCorrosion resistant coatingsCorrosive effectsFused saltsGrowth kineticsHigh temperature corrosionHVOF thermal sprayingNickel coatingsOxidationSodium sulfateSprayed coatingsSteel corrosionVanadium pentoxideBoiler tube steelsCoated steelCorrosion behaviourCyclic oxidationHigh temperature coatingsHigh velocity oxy fuelHot corrosionIndustrial boilersMolten saltOxidation and hot corrosionsAluminum oxide