Reaction of a Molten Cr-Si-Base Alloy with Ceramics and a High Entropy Oxide
Due to their higher thermal and chemical stability than other high-temperature materials, chromium-silicon-base (Cr-Si-base) alloys are promising materials for future gas turbines and other high-temperature applications operating under harsh conditions. To enable near-net-shape casting of Cr-Si-base...
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Veröffentlicht in: | High temperature corrosion of materials 2024-10, Vol.101 (5), p.897-909 |
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Sprache: | eng |
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Zusammenfassung: | Due to their higher thermal and chemical stability than other high-temperature materials, chromium-silicon-base (Cr-Si-base) alloys are promising materials for future gas turbines and other high-temperature applications operating under harsh conditions. To enable near-net-shape casting of Cr-Si-base alloys, a compatibility of the alloy melt with the ceramic crucibles and molds is necessary. Additionally, a metal-ceramic contact exists at the interface between thermal barrier coating (TBC) and alloy, where metallic may melts play a role in the case of coating failure and overheating. In this study, molten Cr
92
Si
8
(in at. %) alloy is brought into contact with powders of ceramics commonly used for casting molds or crucibles (e.g. ZrSiO
4
, Al
2
O
3
, 3YSZ), to investigate liquid metal corrosion, interdiffusion, and stabilities. Additionally, the high entropy oxide (Sm
0.2
Gd
0.2
Dy
0.2
Er
0.2
Yb
0.2
)
2
Zr
2
O
7
(HEO), a potential future TBC material, is investigated. Before melting using an electric arc furnace, the powders of the investigated ceramics were mixed with pulverized Cr
92
Si
8
and pressed into alloy-ceramic pairs, to maximize the contact area between molten metal and ceramic. For microstructural investigations and phase analysis, the materials were assessed using scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The widely used mold material ZrSiO
4
and the coating BN were found to decompose, while reaction products of SiO
2
and CoAl
2
O
4
with the melt were detected. Al
2
O
3
, 3YSZ, and the HEO did not show decomposition or corrosion by the melt. Al
2
O
3
, 3YSZ, and the HEO are therefore considered as promising crucible, mold, and TBC materials for Cr-Si-base alloys. |
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ISSN: | 2731-8397 0030-770X 2731-8400 1573-4889 |
DOI: | 10.1007/s11085-024-10285-4 |