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Fabrication and Characterization of HVOF Sprayed CoNiCrAlY-6%Al2O3 Coating to Improve High-Temperature Oxidation Resistance
Alumina nanoparticles were incorporated into CoNiCrAlY powders to fabricate an overlay coating of improved oxidation resistance for gas turbine blades via thermal spraying. In this regard, 6 wt.% alumina nanoparticles were agglomerated with CoNiCrAlY powders by modified suspension route and applied...
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Published in: | Journal of thermal spray technology 2024-08, Vol.33 (6), p.2104-2116 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites |
Online Access: | Get full text |
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Summary: | Alumina nanoparticles were incorporated into CoNiCrAlY powders to fabricate an overlay coating of improved oxidation resistance for gas turbine blades via thermal spraying. In this regard, 6 wt.% alumina nanoparticles were agglomerated with CoNiCrAlY powders by modified suspension route and applied to samples of CMSX-4 nickel-based superalloy by high velocity oxygen fuel (HVOF) process. The coatings were characterized by X-ray diffraction, scanning electron microscopy and field emission scanning electron microscopy, EDS and elemental mapping, Vickers hardness and roughness measurement. Cyclic oxidation tests were performed to study the high-temperature oxidation behavior at 1100 °C. The results showed an increase in hardness, roughness and porosity with the addition of alumina nanoparticles to the coating. Furthermore, the oxidation resistance of CoNiCrAlY + 6 wt.% Al
2
O
3
was improved as compared to conventional CoNiCrAlY after 100 cycles of oxidation; a reduction in the thickness of oxide layer and β depletion zone was observed. Formation of a dense and protective α-Al
2
O
3
phase, instead of θ-Al
2
O
3
, was confirmed during the oxidation process in the coatings containing nanoparticles. It was concluded that nanoparticles prevent the penetration of elements to the surface and reduce the formation of non-protective oxide layer. |
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ISSN: | 1059-9630 1544-1016 |
DOI: | 10.1007/s11666-024-01829-w |