Investigation of lanthanum pyrochlore-lanthanum phosphate (La2Zr2O7.LaPO4) composite coatings for high-temperature CMAS corrosion resistance in TBCs.
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| Title: | Investigation of lanthanum pyrochlore-lanthanum phosphate (La |
|---|---|
| Authors: | Kumarasamy, Karthikeyan1 (AUTHOR) karthiken96@gmail.com, Rohan, Umapriya2 (AUTHOR), Sudandaradoss, Manisha Vidyavathy1 (AUTHOR) |
| Source: | Bulletin of Materials Science. Jun2026, Vol. 49 Issue 2, p1-21. 21p. |
| Subjects: | Composite coating, Corrosion resistance, Thermal barrier coatings, Lanthanum compounds, Inorganic compounds |
| Abstract: | Solid-particle contaminants rich in CaO–MgO–Al2O3–SiO2 (CMAS) remain a dominant life- limiting factor for thermal-barrier coatings (TBCs) in modern gas turbines. Standard 8 wt.% yttria-stabilized zirconia (YSZ) topcoats, although thermally efficient, permit molten CMAS to penetrate their splat network, triggering phase destabilization and accelerated spallation. To counter this weakness, we designed a multilayer architecture that marries YSZ with a lanthanum pyrochlore lanthanum phosphate (LPZ) composite expected to neutralize CMAS chemically while preserving thermal insulation. Four variants were fabricated by atmospheric plasma-spraying pure YSZ (200 µm) and three hybrid stacks containing 50, 100, or 150 µm of LPZ beneath progressively thinner YSZ caps over NiCrAlY bond-coated INCONEL 718 substrates. All specimens were exposed to a 10 mg cm-2 CMAS overlay at 1200°C for 8–48h. Pre- and post-exposure characterization employed 3-D profilometry, scanning electron microscopy with energy-dispersive spectroscopy, and X-ray diffraction. Increasing the LPZ fraction systematically reduced columnar gap width, porosity, and roughness growth. The richest LPZ coating (50 µm YSZ/150 µm LPZ) curtailed CMAS ingress to ~50 µm after 48 h one quarter of the depth measured in monolithic YSZ and retained >90% of its initial hardness. X-ray analysis revealed the in situ formation of a dense apatite layer, Ca3La7(PO3)(SiO3)5O2, that sealed residual pathways and blocked further attack. The study confirms that integrating a reactive LPZ sub-layer transforms a conventional YSZ topcoat into a reactive protective layer formation, offering a viable route to longer component life and higher permissible firing temperatures in CMAS-laden environments. [ABSTRACT FROM AUTHOR] |
| Copyright of Bulletin of Materials Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Header | DbId: egs DbLabel: Engineering Source An: 193389829 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Investigation of lanthanum pyrochlore-lanthanum phosphate (La<subscript>2</subscript>Zr<subscript>2</subscript>O<subscript>7</subscript>.LaPO<subscript>4</subscript>) composite coatings for high-temperature CMAS corrosion resistance in TBCs. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Kumarasamy%2C+Karthikeyan%22">Kumarasamy, Karthikeyan</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> karthiken96@gmail.com</i><br /><searchLink fieldCode="AR" term="%22Rohan%2C+Umapriya%22">Rohan, Umapriya</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Sudandaradoss%2C+Manisha+Vidyavathy%22">Sudandaradoss, Manisha Vidyavathy</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Bulletin+of+Materials+Science%22">Bulletin of Materials Science</searchLink>. Jun2026, Vol. 49 Issue 2, p1-21. 21p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Composite+coating%22">Composite coating</searchLink><br /><searchLink fieldCode="DE" term="%22Corrosion+resistance%22">Corrosion resistance</searchLink><br /><searchLink fieldCode="DE" term="%22Thermal+barrier+coatings%22">Thermal barrier coatings</searchLink><br /><searchLink fieldCode="DE" term="%22Lanthanum+compounds%22">Lanthanum compounds</searchLink><br /><searchLink fieldCode="DE" term="%22Inorganic+compounds%22">Inorganic compounds</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Solid-particle contaminants rich in CaO–MgO–Al2O3–SiO2 (CMAS) remain a dominant life- limiting factor for thermal-barrier coatings (TBCs) in modern gas turbines. Standard 8 wt.% yttria-stabilized zirconia (YSZ) topcoats, although thermally efficient, permit molten CMAS to penetrate their splat network, triggering phase destabilization and accelerated spallation. To counter this weakness, we designed a multilayer architecture that marries YSZ with a lanthanum pyrochlore lanthanum phosphate (LPZ) composite expected to neutralize CMAS chemically while preserving thermal insulation. Four variants were fabricated by atmospheric plasma-spraying pure YSZ (200 µm) and three hybrid stacks containing 50, 100, or 150 µm of LPZ beneath progressively thinner YSZ caps over NiCrAlY bond-coated INCONEL 718 substrates. All specimens were exposed to a 10 mg cm-2 CMAS overlay at 1200°C for 8–48h. Pre- and post-exposure characterization employed 3-D profilometry, scanning electron microscopy with energy-dispersive spectroscopy, and X-ray diffraction. Increasing the LPZ fraction systematically reduced columnar gap width, porosity, and roughness growth. The richest LPZ coating (50 µm YSZ/150 µm LPZ) curtailed CMAS ingress to ~50 µm after 48 h one quarter of the depth measured in monolithic YSZ and retained >90% of its initial hardness. X-ray analysis revealed the in situ formation of a dense apatite layer, Ca3La7(PO3)(SiO3)5O2, that sealed residual pathways and blocked further attack. The study confirms that integrating a reactive LPZ sub-layer transforms a conventional YSZ topcoat into a reactive protective layer formation, offering a viable route to longer component life and higher permissible firing temperatures in CMAS-laden environments. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Bulletin of Materials Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1007/s12034-026-03576-w Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 21 StartPage: 1 Subjects: – SubjectFull: Composite coating Type: general – SubjectFull: Corrosion resistance Type: general – SubjectFull: Thermal barrier coatings Type: general – SubjectFull: Lanthanum compounds Type: general – SubjectFull: Inorganic compounds Type: general Titles: – TitleFull: Investigation of lanthanum pyrochlore-lanthanum phosphate (La2Zr2O7.LaPO4) composite coatings for high-temperature CMAS corrosion resistance in TBCs. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Kumarasamy, Karthikeyan – PersonEntity: Name: NameFull: Rohan, Umapriya – PersonEntity: Name: NameFull: Sudandaradoss, Manisha Vidyavathy IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 06 Text: Jun2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 02504707 Numbering: – Type: volume Value: 49 – Type: issue Value: 2 Titles: – TitleFull: Bulletin of Materials Science Type: main |
| ResultId | 1 |
