火山灰烧结RE2Si2O7（RE = Yb和Ho）环境阻挡涂层材料的高温腐蚀性能研究

Ayahisa Okawa; Son Thanh Nguyen; Tadachika Nakayama; Thi-Mai-Dung Do; Hisayuki Suematsu; Shu Yin; Takuya Hasegawa; Tsuneo Suzuki; Takashi Goto; Koichi Niihara

doi:10.1007/s12613-024-2899-3

Volume 31 Issue 7

Jul. 2024

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文章导航 > 矿物冶金与材料学报（英文） > 2024 > 31(7): 1628-1638

Ayahisa Okawa, Son Thanh Nguyen, Tadachika Nakayama, Thi-Mai-Dung Do, Hisayuki Suematsu, Shu Yin, Takuya Hasegawa, Tsuneo Suzuki, Takashi Goto, and Koichi Niihara, High-temperature corrosion of sintered RE₂Si₂O₇ (RE = Yb and Ho) environmental barrier coating materials by volcanic ash, Int. J. Miner. Metall. Mater., 31(2024), No. 7, pp. 1628-1638. https://doi.org/10.1007/s12613-024-2899-3

Cite this article as:

Ayahisa Okawa, Son Thanh Nguyen, Tadachika Nakayama, Thi-Mai-Dung Do, Hisayuki Suematsu, Shu Yin, Takuya Hasegawa, Tsuneo Suzuki, Takashi Goto, and Koichi Niihara, High-temperature corrosion of sintered RE2Si2O7 (RE = Yb and Ho) environmental barrier coating materials by volcanic ash, Int. J. Miner. Metall. Mater., 31(2024), No. 7, pp. 1628-1638. https://doi.org/10.1007/s12613-024-2899-3

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研究论文

火山灰烧结RE₂Si₂O₇（RE = Yb和Ho）环境阻挡涂层材料的高温腐蚀性能研究

1)
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
2)
Department of Creative Engineering, National Institute of Technology, Kushiro 084-0916, Japan
3)
Extreme Energy-Density Research Institute, Nagaoka University of Technology, Nagaoka 940-2188, Japan
4)
Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan

通讯作者:
Ayahisa Okawa E-mail: ayahisa.okawa@tohoku.ac.jp

Tadachika Nakayama E-mail: nky15@vos.nagaokaut.ac.jp

中文摘要

稀土硅酸盐是一种很有前途的环境阻挡涂层（EBCs），可以保护下一代燃气轮机叶片中的SiC_f/SiC_m基体。值得注意的是，RE₂Si₂O₇（RE = Yb和Ho）因其与基材相容的热膨胀系数（CTE）和对水蒸气腐蚀的高抵抗性而显示出巨大的潜力。下一代涡轮叶片的目标工作温度为1400°C。在与熔融火山灰粘附的过程中，腐蚀是不可避免的，因此，了解材料的腐蚀行为对其可靠性至关重要。本文使用固态反应和热压方法制备了样品，然后将分别暴露在1400^oC的火山灰中2、24和48 h，研究发现暴露48 h后，火山灰没有与Yb₂Si₂O₇反应，而是渗透到其内部造成损坏。同时，Ho₂Si₂O₇部分溶解在熔融的火山灰中，形成了一个反应区，阻止火山灰熔体穿透内部。随着热处理时间的增加，反应区扩大，针状磷灰石晶粒厚度增加。Yb₂Si₂O₇的残余火山灰中的Ca:Si摩尔比基本上没有变化，但随着时间的推移，Ho₂Si₂O₇的Ca∶Si摩尔比显著降低。火山灰中的Ca被消耗并形成磷灰石，表明具有大离子半径（Ho>Yb）的RE³⁺离子容易从火山灰中沉淀磷灰石。

关键词:

Research Article

High-temperature corrosion of sintered RE₂Si₂O₇ (RE = Yb and Ho) environmental barrier coating materials by volcanic ash

+ Author Affiliations

1)
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
2)
Department of Creative Engineering, National Institute of Technology, Kushiro 084-0916, Japan
3)
Extreme Energy-Density Research Institute, Nagaoka University of Technology, Nagaoka 940-2188, Japan
4)
Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan

Shu Yin is an editorial board member for this journal and was not involved in the editorial review or the decision to publish this article. The authors declare no conflicts of interest associated with this manuscript.
The online version contains supplementary material available at https://doi.org/10.1007/s12613-024-2899-3.

Corresponding authors:
Ayahisa Okawa E-mail: ayahisa.okawa@tohoku.ac.jp

Tadachika Nakayama E-mail: nky15@vos.nagaokaut.ac.jp
Received: 31 October 2023; Revised: 27 March 2024; Accepted: 2 April 2024; Available online: 3 April 2024

Abstract

Abstract

Rare-earth silicates are promising environmental barrier coatings (EBCs) that can protect SiC_f/SiC_m substrates in next-generation gas turbine blades. Notably, RE₂Si₂O₇ (RE = Yb and Ho) shows potential as an EBC due to its coefficient of thermal expansion (CTE) compatible with substrates and high resistance to water vapor corrosion. The target operating temperature for next-generation turbine blades is 1400°C. Corrosion is inevitable during adhesion to molten volcanic ash, and thus, understanding the corrosion behavior of the material is crucial to its reliability. This study investigates the high-temperature corrosion behavior of sintered RE₂Si₂O₇ (RE = Yb and Ho). Samples were prepared using a solid-state reaction and hot-press method. They were then exposed to volcanic ash at 1400°C for 2, 24, and 48 h. After 48 h of exposure, volcanic ash did not react with Yb₂Si₂O₇ but penetrated its interior, causing damage. Meanwhile, Ho₂Si₂O₇ was partially dissolved in the molten volcanic ash, forming a reaction zone that prevented volcanic ash melts from penetrating the interior. With increasing heat treatment time, the reaction zone expanded, and the thickness of the acicular apatite grains increased. The Ca:Si ratios in the residual volcanic ash were mostly unchanged for Yb₂Si₂O₇ but decreased considerably over time for Ho₂Si₂O₇. The Ca in volcanic ash was consumed and formed apatite, indicating that RE³⁺ ions with large ionic radii (Ho > Yb) easily precipitated apatite from the volcanic ash.
- environmental barrier coating;
- volcanic ash;
- rare-earth disilicate;
- corrosion

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