Mass transfer mechanism in Yb2Si2O7 under oxygen potential gradients at high temperatures

被引：0

作者：

Kitaoka S. ^{[1
]}

Matsudaira T. ^{[1
]}

Wada M. ^{[1
]}

Kawashima N. ^{[1
]}

Yokoe D. ^{[1
]}

Kato T. ^{[1
]}

Takata M. ^{[1
]}

机构：

[1] Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya

来源：

| 2018年 / Wiley Blackwell卷 / 263期

基金：

日本科学技术振兴机构;

关键词：

Mass transfer mechanism; Oxygen permeability; Oxygen permeation; Oxygen potential gradients; Ytterbium;

D O I：

10.1002/9781119407270.ch19

中图分类号：

学科分类号：

摘要：

The oxygen permeability of polycrystalline Yb2Si2O7 wafers having a thickness of several hundred microns and serving as model environmental barrier coating (EBC) layers were evaluated under steep oxygen potential gradients (dµo ) at high temperatures. These dµo were produced by exposing the upper and lower surfaces of wafers to atmospheres with different oxygen partial pressures (PO2). The resulting data were compared with literature data for mullite and Al2O3. It was found that the oxygen permeation of Yb2Si2O7 is controlled by grain boundary (GB) diffusion of oxygen from the high PO2 surface to the low PO2 surface, with simultaneous GB diffusion of ytterbium in the opposite direction. Oxygen permeation associated with the GB diffusion of silicon was negligibly small compared to that generated by ytterbium GB diffusion. The concurrent GB diffusion of oxygen and single cations proceeds without acceleration or inhibition due to interdiffusion, and can be described by the Gibbs-Duhem equation, as can the mullite and Al2O3 data. The oxygen permeability constant for Yb2Si2O7, normalized by the GB density, was significantly larger than those for mullite and Al2O3. © 2017 The American Ceramic Society.

引用

页码：187 / 195

页数：8

共 11 条

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