High emittance plasma sprayed ZrO2-Y2O3/La2Zr2O7 thermal barrier coatings for potential application in scramjets

Gopinath, NK and Dan, A and Aruna, ST and Govindarajan, KV and Jagadeesh, G and Barshilia, HC and Roy Mahapatra, D (2024) High emittance plasma sprayed ZrO2-Y2O3/La2Zr2O7 thermal barrier coatings for potential application in scramjets. In: Applied Surface Science, 652 .

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Abstract

In this study, an investigation was conducted on the thermal barrier coatings, focusing on their applicability for radiative cooling in the external airframe of the scramjet intake. ZrO2-8 wt Y2O3 and La2Zr2O7 were plasma sprayed onto Inconel 718 substrate with a bond coat of NiCrAlY. The findings revealed that a maximum emittance of 0.83 ± 0.02 at 973 K was exhibited by Inconel/NiCrAlY/ZrO2-Y2O3 (INY) and maintained good thermal stability up to 1373 K for 2 h in the air. Inconel/NiCrAlY/ZrO2-Y2O3/La2Zr2O7 (INYL) showed a maximum emittance of 0.92 ± 0.02 at 773 K but experienced degradation at higher temperatures. In the thermal exposure temperature range of 298�1373 K, an average emittance of 0.81 ± 0.02 was possessed by INY, while INYL had an average emittance of 0.85 ± 0.05. The thermal stress-induced coating failure and the sintering effect led to the degradation of INYL, while INY exhibited reliable performance while exposed to high temperatures. Computational analysis indicated a reduction of � 230 K wall temperature in the Mach 7 scramjet intake upon using the coatings on Inconel. In summary, the developed plasma spray coatings on Inconel substrate have potential use in scramjet for radiative cooling-based passive thermal management. © 2024 Elsevier B.V.

Item Type:	Journal Article
Publication:	Applied Surface Science
Publisher:	Elsevier B.V.
Additional Information:	The copyright for this article belongs to Elsevier B.V.
Keywords:	Binary alloys; Lanthanum compounds; Plasma jets; Plasma spraying; Sintering; Thermal barrier coatings; Zirconia, Atmospheric plasma spray; Bond coats; Emittances; High emittance; Highest temperature; Inconel; Inconel-718; Plasma-sprayed; Radiative cooling; Thermal exposure, Thermodynamic stability
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering) Others
Date Deposited:	29 Feb 2024 11:09
Last Modified:	29 Feb 2024 11:09
URI:	https://eprints.iisc.ac.in/id/eprint/83873

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