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Indexed by:期刊论文

Date of Publication:2011-11-01

Journal:MATERIALS CHARACTERIZATION

Included Journals:Scopus、SCIE、EI

Volume:62

Issue:11

Page Number:1066-1070

ISSN No.:1044-5803

Key Words:Microstructure; Oxidation; Metal/ceramic laminates; Physical vapor deposition

Abstract:Two NiCoCrAl/ZrO(2)-Y(2)O(3) microlaminates (A and B) were fabricated by electron beam physical vapor deposition, which were different in layer number and metal-layer thickness. The layer number was 20 and 26, respectively. And the metal-layer thickness was 35 and 14 mu m, respectively. The microstructure and isothermal oxidation behavior were investigated. During the exposure in air at 1000 degrees C for 100 h, the t to m phase transformation occurred in the ceramic layers, and oxide scales formed at the surfaces of not only the outer metal-layers but also the internal metal-layers for the microlaminates. The oxidation rate of microlaminate B was greater than that of microlaminate A. Their overall mass gains were significantly dependent on the number and thickness of the metal-layers. The oxidation products were also influenced by metal-layer thickness. Oxide scales of the 35 mu m thick metal-layer microlaminate (A) consisted mainly of alpha-Al(2)O(3) and theta-Al(2)O(3), while the oxidation products of the 14 mu m thick metal-layer microlaminate (B) were the mixture of alpha-Al(2)O(3), theta-Al(2)O(3) and Cr(2)O(3). It was also found that the growth of the oxide scale adjacent to the top YSZ layer was controlled by the oxygen diffusion, and that the growth of the oxide scale adjacent to the internal YSZ layer was controlled by the metal ionic diffusion. (C) 2011 Elsevier Inc. All rights reserved.