High-entropy environmental barrier coating for the ceramic matrix composites

2019 ◽  
Vol 39 (7) ◽  
pp. 2574-2579 ◽  
Author(s):  
Yu Dong ◽  
Ke Ren ◽  
Yonghong Lu ◽  
Qiankun Wang ◽  
Jia Liu ◽  
...  
Keyword(s):  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Composites ◽  
Environmental Barrier ◽  
High Entropy ◽  
Environmental Barrier Coating ◽  
Barrier Coating

scholarly journals Rear Earth Oxide Multilayer Deposited by Plasma Spray-Physical Vapor Deposition for Envisaged Application as Thermal/Environmental Barrier Coating

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 889
Author(s):  
Jie Zhong ◽  
Dongling Yang ◽  
Shuangquan Guo ◽  
Xiaofeng Zhang ◽  
Xinghua Liang ◽  
...  
Keyword(s):  
Composite Coating ◽  
High Temperatures ◽  
Physical Vapor Deposition ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Composites ◽  
Environmental Barrier ◽  
Chemical Attack ◽  
Environmental Barrier Coating ◽  
Barrier Coating

SiC fiber-reinforced SiC ceramic matrix composites (SiCf/SiC CMCs) are being increasingly used in the hot sections of gas turbines because of their light weight and mechanical properties at high temperatures. The objective of this investigation was the development of a thermal/environmental barrier coating (T/EBC) composite coating system consisting of an environmental barrier coating (EBC) to protect the ceramic matrix composites from chemical attack and a thermal barrier coating (TBC) that insulates and reduces the ceramic matrix composites substrate temperature for increased lifetime. In this paper, a plasma spray-physical vapor deposition (PS-PVD) method was used to prepare multilayer Si–HfO2/Yb2Si2O7/Yb2SiO5/Gd2Zr2O7 composite coatings on the surface of SiCf/SiC ceramic matrix composites. The purpose of this study is to develop a coating with resistance to high temperatures and chemical attack. Different process parameters are adopted, and their influence on the microstructure characteristics of the coating is discussed. The water quenching thermal cycle of the coating at high temperatures was tested. The results show that the structure of the thermal/environmental barrier composite coating changes after water quenching because point defects and dislocations appear in the Gd2Zr2O7 and Yb2SiO5 coatings. A phase transition was found to occur in the Yb2SiO5 and Yb2Si2O7 coatings. The failure mechanism of the T/EBC composite coating is mainly spalling when the top layer penetrates cracks and cracking occurs in the interface of the Si–HfO2/Yb2Si2O7 coating.

scholarly journals YAlO3—A Novel Environmental Barrier Coating for Al2O3/Al2O3–Ceramic Matrix Composites

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 609 ◽  
Author(s):  
Caren Gatzen ◽  
Daniel Emil Mack ◽  
Olivier Guillon ◽  
Robert Vaßen
Keyword(s):  
Plasma Spraying ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Atmospheric Plasma ◽  
Aluminum Silicate ◽  
Matrix Composites ◽  
Surface Pretreatment ◽  
X Ray ◽  
Environmental Barrier ◽  
Barrier Coating

Ceramic matrix composites (CMCs) are promising materials for high-temperature applications. Environmental barrier coatings (EBCs) are needed to protect the components against water vapor attack. A new potential EBC material, YAlO3, was studied in this paper. Different plasma-spraying techniques were used for the production of coatings on an alumina-based CMC, such as atmospheric plasma spraying (APS) and very low pressure plasma spraying (VLPPS). No bond coats or surface treatments were applied. The performance was tested by pull–adhesion tests, burner rig tests, and calcium-magnesium-aluminum-silicate (CMAS) corrosion tests. The samples were subsequently analyzed by means of X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Special attention was paid to the interaction at the interface between coating and substrate. The results show that fully crystalline and good adherent YAlO3 coatings can be produced without further substrate preparation such as surface pretreatment or bond coat application. The formation of a thin reaction layer between coating and substrate seems to promote adhesion.

scholarly journals Preparation and properties of CMAS resistant bixbyite structured high-entropy oxides RE2O3 (RE = Sm, Eu, Er, Lu, Y, and Yb): Promising environmental barrier coating materials for Al2O3f/Al2O3 composites

2021 ◽  
Vol 10 (3) ◽  
pp. 596-613 ◽  
Author(s):  
Yanan Sun ◽  
Huimin Xiang ◽  
Fu-Zhi Dai ◽  
Xiaohui Wang ◽  
Yan Xing ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Ceramic Matrix Composites ◽  
Mechanical And Thermal Properties ◽  
Coating Materials ◽  
Environmental Barrier ◽  
High Entropy ◽  
Thermal Expansion Coefficients ◽  
Environmental Barrier Coating ◽  
Barrier Coating

AbstractY2O3 is regarded as one of the potential environmental barrier coating (EBC) materials for Al2O3f/Al2O3 ceramic matrix composites owing to its high melting point and close thermal expansion coefficient to Al2O3. However, the relatively high thermal conductivity and unsatisfactory calcium-magnesium-aluminosilicate (CMAS) resistance are the main obstacles for the practical application of Y2O3. In order to reduce the thermal conductivity and increase the CMAS resistance, four cubic bixbyite structured high-entropy oxides RE2O3, including (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3, (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3, (Sm0.2Eu0.2Er0.2Y0.2Yb0.2)2O3, and (Sm0.2Eu0.2Lu0.2Y0.2Yb0.2)2O3 were designed and synthesized, among which (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 and (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 bulks were prepared by spark plasma sintering (SPS) to investigate their mechanical and thermal properties as well as CMAS resistance. The mechanical properties of (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 and (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 are close to those of Y2O3 but become more brittle than Y2O3. The thermal conductivities of (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 and (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 (5.1 and 4.6 W·m−1·K−1) are only 23.8% and 21.5% respectively of that of Y2O3 (21.4 W·m−1·K−1), while their thermal expansion coefficients are close to those of Y2O3 and Al2O3. Most importantly, HE RE2O3 ceramics exhibit good CMAS resistance. After being attacked by CMAS at 1350 °C for 4 h, the HE RE2O3 ceramics maintain their original morphologies without forming pores or cracks, making them promising as EBC materials for Al2O3f/Al2O3 composites.

scholarly journals Ceramic Matrix Composite Vane Subelement Burst Testing

2006 ◽  
Author(s):  
David N. Brewer ◽  
Michael Verrilli ◽  
Anthony Calomino
Keyword(s):  
High Pressure ◽  
Matrix Composite ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix ◽  
Environmental Barrier ◽  
Environmental Barrier Coating ◽  
Barrier Coating

Burst tests were performed on Ceramic Matrix Composite (CMC) vane specimens, manufactured by two vendors, under the Ultra Efficient Engine Technology (UEET) project. Burst specimens were machined from the ends of 76mm long vane sub-elements blanks and from High Pressure Burner Rig (HPBR) tested specimens. The results of burst tests will be used to compare virgin specimens with specimens that have had an Environmental Barrier Coating (EBC) applied, both HPBR tested and untested, as well as a comparison between vendors.

scholarly journals Environmental Barrier Coatings Made by Different Thermal Spray Technologies

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 784 ◽  
Author(s):  
Robert Vaßen ◽  
Emine Bakan ◽  
Caren Gatzen ◽  
Seongwong Kim ◽  
Daniel Emil Mack ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Thermal Spray ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Atmospheric Plasma ◽  
Matrix Composites ◽  
Barrier Coatings ◽  
Environmental Barrier Coatings ◽  
Environmental Barrier ◽  
Thermal Expansion Coefficients

Environmental barrier coatings (EBCs) are essential to protect ceramic matrix composites against water vapor recession in typical gas turbine environments. Both oxide and non-oxide-based ceramic matrix composites (CMCs) need such coatings as they show only a limited stability. As the thermal expansion coefficients are quite different between the two CMCs, the suitable EBC materials for both applications are different. In the paper examples of EBCs for both types of CMCs are presented. In case of EBCs for oxide-based CMCs, the limited strength of the CMC leads to damage of the surface if standard grit-blasting techniques are used. Only in the case of oxide-based CMCs different processes as laser ablation have been used to optimize the surface topography. Another result for many EBCs for oxide-based CMC is the possibility to deposit them by standard atmospheric plasma spraying (APS) as crystalline coatings. Hence, in case of these coatings only the APS process will be described. For the EBCs for non-oxide CMCs the state-of-the-art materials are rare earth or yttrium silicates. Here the major challenge is to obtain dense and crystalline coatings. While for the Y2SiO5 a promising microstructure could be obtained by a heat-treatment of an APS coating, this was not the case for Yb2Si2O7. Here also other thermal spray processes as high velocity oxygen fuel (HVOF), suspension plasma spraying (SPS), and very low-pressure plasma spraying (VLPPS) are used and the results described mainly with respect to crystallinity and porosity.

Environmental Barrier Coating Oxidation and Adhesion Strength

2020 ◽  
Author(s):  
Bryan J. Harder ◽  
Michael J. Presby ◽  
Jon A. Salem ◽  
Steven M. Arnold ◽  
Subodh K. Mital
Keyword(s):  
Adhesion Strength ◽  
Physical Vapor Deposition ◽  
Ceramic Matrix Composites ◽  
Thermally Grown Oxide ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Environmental Barrier Coatings ◽  
Environmental Barrier ◽  
Barrier Coating ◽  
Coating Durability

Abstract Plasma Spray-Physical Vapor Deposition (PS-PVD) environmental barrier coatings (EBCs) of Yb2Si2O7 were deposited on SiC and exposed in a steam environment (90% H2O/O2) at 1426°C to form a thermally grown oxide (TGO) layer between the substrate and EBC. In advanced ceramic material systems such as coated ceramic matrix composites (CMCs), the TGO layer is the weak interface in coated CMC systems and directly influences component lifetimes. The effect of surface roughness and TGO thickness on the adhesion strength were evaluated by mechanical testing of the coatings after exposure. Morphology and oxide layer thickness were analyzed with electron microscopy while the composition and crystal structure were tracked with X-ray diffraction. The strength of the system is evaluated with respect to oxidation rate to give a qualitative understanding of coating durability.

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