Accelerated Hot Corrosion Studies of D-Gun-Sprayed Cr2O3–50% Al2O3 Coating on Boiler Steel and Fe-Based Superalloy

Autor: Amita Rani, C. M. Gupta, Niraj Bala
Rok vydání: 2017
Předmět:
Zdroj: Oxidation of Metals. 88:621-648
ISSN: 1573-4889
0030-770X
DOI: 10.1007/s11085-017-9759-8
Popis: In the current investigation, Cr2O3–50% Al2O3 coating was deposited on ASTM-SA213-T-22 boiler steel and Fe-based superalloy Superfer 800H by D-gun spray process. The high-temperature corrosion performance of the coated as well as bare alloys was evaluated in Na2SO4–60%V2O5 molten salt, an aggressive environment at 900 °C under cyclic conditions. The kinetics of the corrosion were analyzed by the change in weight measurements which were taken after each cycle (i.e., 1-h heating in a tube furnace followed by 20-min cooling in ambient air) for a total period of 50 cycles. The X-ray diffraction and scanning electron microscopy/energy-dispersive X-ray analysis techniques were used for the analysis of corrosion products. During investigations, it was found that both the selected bare alloys have suffered intensive spallation in the form of removal of their oxide scales, which may be attributed to the formation of non-protective Fe2O3-dominated oxide scales, whereas the coated alloys have shown lesser weight gains along with better adhesiveness of the oxide scales with the substrate till the end of the experiment. The oxides of chromium and aluminum were the main phases revealed in the oxide scales of the coated specimens, which are reported to be protective against the hot corrosion.
Databáze: OpenAIRE
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