Investigation of the chemical composition of the thermally grown oxide layer in thermal barrier systems with NiCoCrAlY bond coats

被引:25
作者
Mercer, C. [1 ]
Faulhaber, S.
Yao, N.
McIlwrath, K.
Fabrichnaya, O.
机构
[1] Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA
[2] Princeton Univ, Inst Sci & Technol, Princeton, NJ 08544 USA
[3] Hitachi High Technol Amer, Pleasanton, CA 94588 USA
[4] Max Planck Inst Met Res, Stuttgart, Germany
关键词
thermal barrier coatings; thermally grown oxide; NiCoCrAlY; energy-dispersive spectroscopy; hafnia; fluorite;
D O I
10.1016/j.surfcoat.2006.02.024
中图分类号
TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
The morphology and composition of the thermally grown oxide (TGO) layer in a thermal barrier system with a NiCoCrAlY bond coat are characterized by a combination of scanning and transmission electron microscopy, focused ion beam sectioning and energy-dispersive spectroscopy (EDS) element mapping. The investigation has revealed a complex TGO that exhibits numerous thickness inhomogeneities ('pegs'), and a sizable distribution of nano-scale second phase particles. These particles have been determined to be of two types: regions of entrained bond coat and oxides based on Y2O3 and HfO2. The most probable phase makeup of the oxides is a cubic fluorite of approximate composition 4HfO(2)-Y2O3. Diffusion of Hf and Y from the bond coat or entrapment of bond coat elements during TGO growth are the most likely mechanisms for the formation of these oxide particles. (c) 2006 Elsevier B.V. All rights reserved.
引用
收藏
页码:1495 / 1502
页数:8
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