Functionally graded ZrO2-NiCrAlY coatings prepared by plasma spraying using pre-mixed, spheroidized powders

Gu, Yan-Wei, Khor, Khiam Aik, Fu, Yong Qing and Wang, Y. (1997) Functionally graded ZrO2-NiCrAlY coatings prepared by plasma spraying using pre-mixed, spheroidized powders. Surface and Coatings Technology, 96 (2-3). pp. 305-312. ISSN 0257-8972

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Abstract

Functionally graded ZrO2-NiCrAlY coatings were prepared by plasma spraying. Pre-mixed, plasma spheroidized powders were used as the feedstock. The advantage of using pre-mixed, spheroidized powders was to ensure chemical homogeneity and promote uniform density along the graded layers, and these pre-mixed powders are used to form the different interlayers of functionally graded coatings in the present study. The microstructure, density and microhardness changed gradiently in the ZrO2-NiCrAlY FGM (functionally graded materials) coatings. The bond strength of ZrO2-NiCrAlY FGM coatings with different graded layers was measured. Results showed that for as-sprayed coatings with the same thickness, the bond strength increased with the number of graded layers. The bond strength of the FGM coatings with five graded layers was about twice as high as that of the duplex coatings because of the significant reduction of the residual stress in the coatings. Experimental results also showed that the bond strength of as-sprayed FGM coating increased significantly after hot isostatic press (HIP) treatment and the reason can be attributed to the densification of the microstructure, the decrease of defects in the coatings, interdiffusion between layers and reduction in the residual thermal stresses.

Item Type:	Article
Uncontrolled Keywords:	Bond strength; Coating; FGM; Heat treatment; HIP; Plasma spray
Subjects:	F200 Materials Science
Department:	Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User:	Becky Skoyles
Date Deposited:	27 Mar 2015 11:40
Last Modified:	12 Oct 2019 18:32
URI:	http://nrl.northumbria.ac.uk/id/eprint/21902

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