Al2O3---ZrO2 composite coatings for thermal-barrier applications

Ramaswamy, Parvati and Seetharamu, S and Varma, KBR and Rao, KJ (1997) Al2O3---ZrO2 composite coatings for thermal-barrier applications. In: Composites Science and Technology, 57 (1). pp. 81-89.

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Abstract

Graded alternate layers of Al2O3 and 8% Y2O3-ZrO2 and their admixtures were plasma sprayed onto bond-coated mild steel. They were evaluated for thermal-shock resistance, thermal-barrier characteristics, hot corrosion resistance (molten NaCl corrodant) and depth of attack, adhesion strength and the presence of phases. Although front-back temperature drops of 423-623 K were observed, some of the coatings showed good adherence even after 100 thermal shack cycles. In the sequence of the graded layers, the oxide which is directly in contact with the bond coat appears to influence the properties especially in coatings of 150 and 300 mu m thickness. Molten NaCl readily attacks the films at high hot-face temperatures (1273 K for 1 h) and the adhesive strength falls significantly by 50-60%. Diffusion of alkaline elements is also found to depend on the chemical composition of the outer coating directly facing the molten corrodant. (C) 1997 Elsevier Science Limited.

Item Type:	Journal Article
Publication:	Composites Science and Technology
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	composite;multilayer;Al2O3---ZrO2;TBCs
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	02 Jun 2011 10:21
Last Modified:	02 Jun 2011 10:21
URI:	http://eprints.iisc.ac.in/id/eprint/38162

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