Article
Materials Science, Coatings & Films
Shan Li, Wenbo Chen, Lidong Zhao, Hongbo Guo
Summary: (Gd0.9Yb0.1)2Zr2O7 (GYbZ) coatings with quasi-columnar structure prepared by PS-PVD were isothermally exposed to Calcia-magnesia-alumino-silicate (CMAS) at T = 1300 degrees C for various time periods. The resistance of GYbZ coatings against CMAS penetration was examined by wetting test and the reaction products were analyzed. The results showed that a dense reaction layer formed after 1 hour of exposure and the thickness remained almost constant from 1 hour to 100 hours, indicating effective suppression of CMAS penetration. The particles between columns played a significant role in the rapid formation of a CMAS barrier apatite layer.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Yongang Zhang, Jiasen Han, Dongting Wu, Yong Zou
Summary: The addition of 20 wt.% Al2O3-7YSZ effectively reduces the corrosion caused by CMAS and CMAS + NaVO3 salt (CN) on TBCs, and promotes the formation of globular zirconia and interior infiltration in TBCs. This is because the dissolution of Al2O3 into the CMAS/CN melt modifies its thermophysical properties, inducing crystallization and dense layering of the anorthite interfacial reaction product.
Article
Materials Science, Coatings & Films
Xingeng Lei, Yufeng Wang, Quansheng Wang, Li Li, Xianjin Ning
Summary: By fabricating a microstructure modification yttria-stabilized zirconia (YSZ) top coat with a low-porosity fibrous structure layer on the conventional columnar structure layer, the CMAS corrosion resistance of EB-PVD TBCs was significantly enhanced.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Bo Wang, Chengyang Jiang, Ye Chen, Xunuo Lang, Jian He, Hongbo Guo, Yuting Wu, Lulu Pan
Summary: Three types of (Gd0.8Yb0.2)2Zr2O7 (GYbZ)/YSZ double ceramic layer thermal barrier coatings (TBCs) with different microstructures were prepared using electron beam physical vapor deposition. The CMAS corrosion performance of these TBCs was studied and it was found that the microstructure strongly influenced the CMAS corrosion resistance. TBCs with smaller inter-column gaps and larger specific surface area exhibited superior CMAS corrosion performance.
Article
Materials Science, Ceramics
Guangheng Zhang, Jie Zhang, Jingyang Wang
Summary: The demand for more powerful aircraft has led to the development of ceramic matrix composites and environmental barrier coatings (EBC). A promising EBC material called ytterbium oxide (Yb2O3) was fabricated through hot pressing and its properties were systematically investigated. The evaluation of its thermal properties provides a baseline for its application on SiCf/SiC or Al2O3f/Al2O3 composites. The material exhibits excellent durability in harsh environments such as water vapor and molten calcium-magnesium-aluminosilicate (CMAS). The thermochemical interactions between ytterbium oxide and CMAS were found to be drastically different from rare-earth silicates due to the absence of silicon oxide. The reaction of ytterbium oxide with CMAS forms a variety of reaction products, including apatite, garnet, and silicocarnotite. The crystallization of garnet and silicocarnotite effectively consumes and solidifies the CMAS melt, preventing further corrosion.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Pawel Pedrak, Kamil Dychton, Marcin Drajewicz, Marek Goral
Summary: The ceramic topcoats of thermal barrier coatings (TBCs) can increase the working temperature of jet engines, with yttria-stabilized zirconia oxide (YSZ) commonly used for this purpose. The development of Re2Zr2O7-type pyrochlores as YSZ replacements shows promise, with a new synthesis concept and technology called reactive PS-PVD resulting in the successful production of a Gd2Zr2O7 (GZO) coating. The microstructure observations, phase composition, and thermal analysis of the GZO coating revealed improved performance compared to conventional YSZ coatings.
Article
Materials Science, Coatings & Films
Kwang-Yong Park, Kyung-Ic Jang, Sang-Won Myoung, Yeon-Gil Jung, Byung-Il Yang, Jun-Seong Kim
Summary: The study investigated various TBC systems with different structural combinations and found that the TBC system with the NoM-YSZ topcoat layer showed excellent performance in both hot corrosion and CMAS tests. The phase stability plays a critical role in the lifetime of TBCs in harsh environments.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Materials Science, Ceramics
Andrew J. Wright, Chuying Huang, Michael J. Walock, Anindya Ghoshal, Muthuvel Murugan, Jian Luo
Summary: The new class of CCFOs shows improved protective properties at intermediate temperatures, but also higher chemical reactivity with sand at elevated temperatures. The high-entropy oxide exhibits no grain boundary penetration at all temperatures, but significant reaction and precipitation occur. Additionally, these materials have higher thermal expansion coefficients compared to conventional materials.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Coatings & Films
Hao Dong, Xinghua Liang, Zifan Wang, Na Luo, Jingqin Zhang, Yongzhong Zhan, Xiaofeng Zhang
Summary: In this study, an Al film was applied on the surface of EB-PVD TBCs and converted to alpha-Al2O3, which improved the lifespan of the TBCs. Alpha-Al2O3 had a toughening effect, enhanced high-temperature oxidation resistance, and prevented CMAS penetration and corrosion. Moreover, Al modification improved surface roughness and wetting resistance of the TBCs.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Longkang Cong, Wei Li, Qiang Song, Yao Guo, Jiancheng Wang, Shengyue Gu, Shouyang Zhang
Summary: This study investigated the CMAS corrosion behavior of high entropy thermal barrier coatings (HEF) material heated at high temperature and found that HEF exhibits good resistance to CMAS corrosion. CMAS can dissolve HEF and re-precipitate stable multicomponent apatite and rare earth-stabilized HfO2. The re-precipitation rate of the apatite phase is positively related to the size of the rare earth cations.
Article
Materials Science, Multidisciplinary
Pingping Liu, Xin Zhong, Yaran Niu, Liping Huang, Hong Li, Dong Fan, Qilian Li, Xuebin Zheng, Jinliang Sun
Summary: This study investigated the reaction behaviors and corrosion mechanisms of tri-layer Yb2SiO5/Yb2Si2O7/Si EBCs against CMAS melts at high temperatures. The results showed that the reaction temperature had a significant impact on the corrosion behaviors of the EBCs, with the Yb2SiO5 top layer exhibiting better corrosion resistance.
Article
Materials Science, Multidisciplinary
Fuhao Cheng, Ziqian Meng, Chufei Cheng, Jiadong Hou, Yufeng Liu, Bei Ren, Haiyan Hu, Feng Gao, Yang Miao, Xiaomin Wang
Summary: As gas turbine inlet temperatures continue to rise, the urgent need for new thermal barrier coating (TBC) materials has been highlighted. This study investigated a new class of high-entropy oxides (HEO) as potential protective coating materials, focusing on their molten silicate corrosion, thermal conductivity, and high-temperature phase stability. The results show that these HEO materials, with composition tuning, exhibit phase stability and low thermal conductivity compared to conventional materials, making them suitable for future applications in thermal protection systems.
Article
Materials Science, Ceramics
Rongxue Yan, Wenping Liang, Qiang Miao, Hui Zhao, Ruixiang Liu, Jingli Li, Kai Zang, Meijing Dong, Xiping He, Xiguang Gao, Yindong Song
Summary: A high entropy zirconate ceramic (Gd0.2Y0.2Er0.2Tm0.2Yb0.2)(2)Zr2O7 (HEZ) with a fluorite structure has been successfully synthesized by solid-state reaction and high-temperature sintering. The HEZ exhibits ultra-low thermal conductivity, similar thermal expansion coefficient to YSZ, excellent mechanical properties, and great CMAS corrosion resistance.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
Shuo Wang, Shijie Zhang, Zong Wang, Chuanyong Qu, Wei Qiu
Summary: In this study, photoluminescence spectroscopy technology was used to nondestructively and accurately characterize the stress caused by calcium-magnesium-alumino-silicate (CMAS) corrosion in thermal barrier coatings (TBCs). TBC specimens were prepared and CMAS corrosion experiments were performed, and a mechanical model based on Ce3+ photoluminescence spectroscopy was derived to investigate the stress in the TBCs. The results revealed the local stress concentration and nonlinear stress distribution caused by CMAS penetration, and the significant influence of corrosion time, temperature, and CMAS concentration on the evolution of the stress field in TBCs.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Coatings & Films
Fatih Kirbiyik, Mustafa Guven Gok, Gultekin Goller
Summary: Investigation of a new type of functionally graded thermal barrier coating for resistance to high-temperature corrosion, using two different test setups to simulate harsh engine environments. Compared to commercial single-layer coatings, the new coating did not undergo phase transformation, while the commercial coating experienced phase transformation after high-temperature testing, resulting in coating failure.
SURFACE & COATINGS TECHNOLOGY
(2022)
