High-Temperature Oxidation Studies of Plasma-Sprayed NiCrAlY/TiO2 and NiCrAlY/Cr2O3/YSZ Cermet Composite Coatings on MDN-420 Special Steel Alloy
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Date
2021
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Publisher
Springer
Abstract
The plasma spray process was used to form 70%NiCrAlY + 30%TiO<inf>2</inf> and 70%NiCrAlY + 25%Cr<inf>2</inf>O<inf>3</inf> + 5%YSZ cermet coatings on MDN-420 special steel alloy. Cyclic oxidation testing was conducted on coated and uncoated specimens at 700°C under a static air environment. Thermogravimetric analysis was applied to establish the oxidation kinetics. X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy-dispersive x-ray spectroscopy (EDS), and electron probe microanalysis (EPMA) techniques were used to analyze the oxidized products. The NiCrAlY + Cr<inf>2</inf>O<inf>3</inf> + YSZ coating was found to be most resistive when compared with the NiCrAlY + TiO<inf>2</inf> coating in the aggressive oxidation environment. Net weight loss was observed for bare MDN-420 alloy due to sputtering. The oxidation resistance of the coatings was due to formation of Cr<inf>2</inf>O<inf>3</inf>, NiCr<inf>2</inf>O<inf>4</inf>, NiO, and Al<inf>2</inf>O<inf>3</inf> phases. © 2021, ASM International.
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Keywords
Alumina, Aluminum oxide, Cermets, Chromium alloys, Composite coatings, Electron probe microanalysis, Nickel oxide, Oxidation resistance, Plasma jets, Plasma spraying, Scanning electron microscopy, Sprayed coatings, Thermogravimetric analysis, Thermooxidation, Titanium dioxide, Yttria stabilized zirconia, Cermet coatings, Cermet composite coating, Cyclic oxidation testing, NiCrAlY/cr2O3/YSZ, NiCrAlY/TiO2, Plasma spray process, Special steel, Special steel alloy, Static air, Thermal spray coatings, Alloy steel
Citation
Metallography, Microstructure, and Analysis, 2021, 10, 5, pp. 642-651