Influence of high-temperature creep stress on growth of thermally grown oxide in thermal barrier coatings
Influence of high-temperature creep stress on growth of thermally grown oxide in thermal barrier coatings
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DOI：
10.1016/j.surfcoat.2009.01.029
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发表时间：
2009-04
影响因子：
5.4
通讯作者：
D. Seo;K. Ogawa;Y. Nakao;H. Miura;T. Shoji
中科院分区：
文献类型：
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作者：
D. Seo;K. Ogawa;Y. Nakao;H. Miura;T. Shoji
最近，发现了很大的局部应力，这是由氧通过现有氧化物的扩散速率和氧化物/氧化材料界面处的化学反应速率的变化引起的。由于热障涂层（TBC）系统中会产生高热应力，新生长的氧化物的体积膨胀和离心力，热生长氧化物（TGO）的生长速率可能会根据温度、暴露时间和应力而变化。本研究的目的是明确静态氧化下应力对TGO厚度生长速率的影响。结果表明，TGO 增厚不仅受到暴露温度增加的影响，而且还受到施加应力的影响。由于施加的载荷，TBC系统中纵向上的拉应力使得氧化剂传输和氧化物流动更容易，即拉应力促进新形成的氧化物的体积膨胀。当施加的应力在900℃下从0增加到205MPa，持续325小时时，TGO厚度的增加率约为34%；当应力在950℃下从0增加到150MPa，持续125小时时，TGO厚度的增加率约为25%。
Recently, a large local stress has been found, caused by the change of both the diffusion rate of oxygen through an existing oxide and the rate of chemical reaction at the oxide/oxidized material interface. Since high thermal stress occurs in the thermal barrier coating (TBC) system, the volume expansion of the newly grown oxide, and centrifugal force, the growth rate of the thermally grown oxide (TGO) may change depending on the temperature, the exposure time, and the stress. The aim of this study is to make clear the influence of stress on the growth rate of the TGO thickness under static oxidation. The results show that TGO thickening was affected by the increase of not only the exposure temperature but also the applied stress. The tensile stress in a longitudinal direction in a TBC system due to the applied load makes the oxidant transport and oxide flow more easy, i.e., the tensile stress promotes a volume expansion of newly formed oxide. The increase rate of the TGO thickness was approximately 34% when the applied stress increased from 0 to 205 MPa at 900 °C for 325 h, and approximately 25% when the stress increased from 0 to 150 MPa at 950 °C for 125 h.