Mechanisms of action of Si in coatings to protect Ni-based superalloy against hot corrosion
Abstract
This study investigates the oxidation and hot corrosion in air at 1000 °C for 24 h of simple and Si-modified Al slurry coatings synthesized on two Ni-based superalloys, DS200+Hf (W-containing) and Rene 77 (Mo-containing). Hot corrosion with Na 2 SO 4 deposits is identified to be more severe than oxidation and is stronger on DS200+Hf, highlighting the dominant role of environment and substrate chemistry. The addition of Si promotes the formation of Cr x Si y (W,Ti) z silicides in DS200+Hf and Cr x Si y silicides in Rene 77. After degradation at 1000 °C, new Co-rich silicides, such as WCoSi and (Nb,Ti) 6 Co 16 Si 7 , are observed, along with Cr oxides. Si also traps refractory elements (W, Mo), limiting acidic fluxing and enhancing corrosion resistance. Atom probe tomography (APT) has revealed the presence of hydrogen in the silicides, potentially associated with PVA from the slurry coating technique. Moreover, scanning transmission electron microscopy (STEM) analyses indicate N may contribute to degradation, competing with Na, S and O.
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BibTeX
@article{piel2026mechanisms,
title = {{Mechanisms of action of Si in coatings to protect Ni-based superalloy against hot corrosion}},
author = {Damien Piel and Paraskevas Kontis and Andreas Undisz and Fernando Pedraza},
journal = {Corrosion Science},
year = {2026},
month = nov,
doi = {10.1016/j.corsci.2026.114390},
url = {https://univ-rochelle.hal.science/hal-05857027v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Mechanisms of action of Si in coatings to protect Ni-based superalloy against hot corrosion
AU - Damien Piel
AU - Paraskevas Kontis
AU - Andreas Undisz
AU - Fernando Pedraza
PY - 2026
DA - 2026/11/09
JO - Corrosion Science
DO - 10.1016/j.corsci.2026.114390
UR - https://univ-rochelle.hal.science/hal-05857027v1
AB - This study investigates the oxidation and hot corrosion in air at 1000 °C for 24 h of simple and Si-modified Al slurry coatings synthesized on two Ni-based superalloys, DS200+Hf (W-containing) and Rene 77 (Mo-containing). Hot corrosion with Na 2 SO 4 deposits is identified to be more severe than oxidation and is stronger on DS200+Hf, highlighting the dominant role of environment and substrate chemistry. The addition of Si promotes the formation of Cr x Si y (W,Ti) z silicides in DS200+Hf and Cr x Si y silicides in Rene 77. After degradation at 1000 °C, new Co-rich silicides, such as WCoSi and (Nb,Ti) 6 Co 16 Si 7 , are observed, along with Cr oxides. Si also traps refractory elements (W, Mo), limiting acidic fluxing and enhancing corrosion resistance. Atom probe tomography (APT) has revealed the presence of hydrogen in the silicides, potentially associated with PVA from the slurry coating technique. Moreover, scanning transmission electron microscopy (STEM) analyses indicate N may contribute to degradation, competing with Na, S and O.
SN - 0010-938X
SN - 1879-0496
ER -