scholarly journals Composition Optimization, High-temperature Stability and Thermal Cycling Performance of Sc-doped Gd2Zr2O7 Thermal Barrier Coatings: Theoretical and Experimental Studies

2021 ◽  
Author(s):  
Lei Guo ◽  
Bowen Li ◽  
Yuxian Cheng ◽  
Lu Wang
Keyword(s):  
Thermal Cycling ◽  
Experimental Studies ◽  
Interface Reaction ◽  
Temperature Stability ◽  
Cycling Performance ◽  
First Principles Calculation ◽  
Thermal Barrier ◽  
Air Plasma ◽  
High Temperature Stability ◽  
Ysz Coating

Abstract Sc was doped into Gd2Zr2O7 for expanding the potential for thermal barrier coating (TBC) applications. According to first-principles calculation, the solid solution mechanism of Sc in Gd2Zr2O7 lattice was revealed, i.e., Sc first occupies the lattice interstitial sites followed by substituting for Gd, and the interstitial Sc concentration is less than 11.11%. By considering the mechanical and thermophysical properties comprehensively, the optimum Sc doping content was determined to be 16.67%, and this composition was selected to produce TBCs by air plasma spraying with YSZ as a bottom ceramic coating (Gd-Sc/YSZ TBC). After sintering at 1400 ℃ for 100 h, Gd-Sc coatings remain phase and structural stability indicative of excellent sintering resistance. By thermal cycling tests, Gd-Sc TBCs fails due to the low toughness and the interface reaction between Gd-Sc and boding coatings, while Gd-Sc/YSZ TBCs exhibit much longer thermal cycling lifetime, and the failure mode is YSZ coating cracking.

scholarly journals Composition Optimization, High-temperature Stability and Thermal Cycling Performance of Sc-doped Gd2Zr2O7 Thermal Barrier Coatings: Theoretical and Experimental Studies

2021 ◽  
Author(s):  
Lei Guo ◽  
Bowen Li ◽  
Yuxian Cheng ◽  
Lu Wang
Keyword(s):  
Thermal Cycling ◽  
Experimental Studies ◽  
Interface Reaction ◽  
Temperature Stability ◽  
Cycling Performance ◽  
First Principles Calculation ◽  
Thermal Barrier ◽  
Air Plasma ◽  
High Temperature Stability ◽  
Ysz Coating

Abstract Sc was doped into Gd2Zr2O7 for expanding the potential for thermal barrier coating (TBC) applications. According to first-principles calculation, solid solution mechanism of Sc in Gd2Zr2O7 lattice was revealed, i.e., Sc atoms first occupy the lattice interstitial sites followed by substituting for Gd, and the interstitial Sc concentration is less than 11.11 at. %. By considering the mechanical and thermophysical properties comprehensively, the optimum Sc doping content was determined to be 16.67 at. %, and this Sc content was selected to produce TBCs by air plasma spraying with YSZ as a bottom ceramic coating (Gd-Sc/YSZ TBC). After sintering at 1400 ℃ for 100 h, Gd-Sc coatings retain phase and structural stability indicative of excellent sintering resistance. By thermal cycling tests, Gd-Sc TBCs fail due to the low toughness and the interface reaction between Gd-Sc and bond coat, while Gd-Sc/YSZ TBCs exhibit much longer thermal cycling lifetime, and the failure mode is YSZ coating cracking.

La2O3 Doped Y2O3 Stabilized ZrO2 TBC Prepared by EB-PVD

2006 ◽  
Vol 317-318 ◽  
pp. 501-504 ◽  
Author(s):  
Mineaki Matsumoto ◽  
Norio Yamaguchi ◽  
Hideaki Matsubara
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
High Resistance ◽  
Thermal Transport ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Microstructural Observation ◽  
Low Thermal Conductivity ◽  
Ysz Coating

Effect of La2O3 addition on thermal conductivity and high temperature stability of YSZ coating produced by EB-PVD was investigated. La2O3 was selected as an additive because it had a significant effect on suppressing densification of YSZ. The developed coating showed extremely low thermal conductivity as well as high resistance to sintering. Microstructural observation revealed that the coating had fine feather-like subcolumns and nanopores, which contributed to limit thermal transport. These nanostructures were thought to be formed by suppressing densification during deposition.

Influence of Bondcoat Topography on the Properties of Suspension Sprayed YSZ Thermal Barrier Coatings

2021 ◽  
Author(s):  
Filofteia-Laura Toma ◽  
Julia Sagel ◽  
Christoph Leyens ◽  
Karel Slámečka ◽  
Serhii Tkachenko ◽  
...  
Keyword(s):  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Thermal Spraying ◽  
Ceramic Coatings ◽  
Cycling Performance ◽  
Thermal Barrier ◽  
Oxide Ceramic ◽  
Air Plasma ◽  
Barrier Coatings ◽  
Direct Laser

Abstract Intensive R&D work of more than one decade has demonstrated many unique coating properties; particularly for oxide ceramic coatings fabricated by suspension thermal spraying technology. Suspension spraying allows producing yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBC) with columnar microstructure; similar to those produced by electron-beam physical vapor deposition (EB-PVD); and vertically cracked morphologies; with a generally low thermal conductivity. Therefore; suspension sprayed YSZ TBCs are seen as an alternative to EB-PVD coatings and those produced by conventional air plasma spray (APS) processes. Nonetheless; the microstructure of the YSZ topcoat is strongly influenced by the properties of the metallic bondcoat. In this work; direct laser interference patterning (DLIP) was applied to texture the surface topography of Ni-alloy based plasma sprayed bondcoat. Suspension plasma spraying (SPS) was applied to produce YSZ coatings on top of as-sprayed and laser-patterned bondcoat. The samples were characterized in terms of microstructure; phase composition and thermal cycling performance. The influence of the bondcoat topography on the properties of suspension sprayed YSZ coatings is presented and discussed.

High temperature Au-based solder reliability in electronic packages for harsh environments

2011 ◽  
Vol 2011 (1) ◽  
pp. 000438-000445
Author(s):  
M.F. Sousa ◽  
S. Riches ◽  
C. Johnston ◽  
P.S. Grant
Keyword(s):  
High Temperature ◽  
Thermal Cycling ◽  
Thermal Shock ◽  
Microstructural Analysis ◽  
Temperature Stability ◽  
Acoustic Microscopy ◽  
Harsh Environments ◽  
Electronic Packages ◽  
High Temperature Stability ◽  
Die Attach

The operation of electronic packages in high temperature environments is a significant challenge for the microelectronics industry, and poses a challenge to the traditional temperature limit of 125°C for high electronic systems, such as those used in down-hole, well-logging and aero-engine applications. The present work aims to develop understanding of how and why attach materials for Si dies degrade/fail under harsh environments by investigating high temperature Au based solders. Au-2wt%Si eutectic melts at < 400°C and offers high temperature stability but high temperature processing and complex manufacturing steps are the major drawbacks. Changes in the die attach material were investigated by isothermal ageing at 350°C, thermal shock and thermal cycling treatments. Die attach reliability investigated by thermal shock and thermal cycling showed that the bonded area degraded. Nevertheless, most of the samples tested had high bonded area ranging from 92.5 to 97.5%. The failure behaviour of the die attach materials included cracking of die and/or attach material, delamination and voiding. Scanning acoustic microscopy images provided a rapid assessment of delamination and other defects and their location within the package. Microstructural analysis and die shear testing were also carried out, along with the high temperature endurance of a SOI test chip for signal conditioning and processing applications at 250°C. All functions evaluated have shown stable performance at 250°C for up to 9000 hours.

Thermal Cycling Behavior of Sm2Zr2O7 Ceramics Thermal Barrier Coatings by APS

2012 ◽  
Vol 512-515 ◽  
pp. 1058-1061
Author(s):  
Xian Kai Sun ◽  
Quan Sheng Wang ◽  
Yan Bo Liu ◽  
Can Wang
Keyword(s):  
Thermal Cycling ◽  
Plasma Spraying ◽  
Thermal Barrier Coatings ◽  
Thermally Grown Oxide ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Coating Failure ◽  
Ysz Coating ◽  
Major Factors

The prochlore structure ceramic of Sm2Zr2O7 was synthesized by chermical coprecipitation method. Then the feedstock powder for plasma spraying was prepared by spray drying with proper distribution of particle size about 30–70μm. The thermal barrier coatings with a topcoat of Sm2Zr2O7 and with a two– layer topcoat of Sm2Zr2O7/YSZ were prepared by atmospheric plasma spraying(APS). The cohesive strength of Sm2Zr2O7/YSZ coating presented a value of 15.49 Mpa and 23.37 Mpa, respectively. Microstructure and phase analyses reveal that plasma spraying of complex Sm2Zr2O7 is accompanied with the formation of the transverse crack networks. the TBCs with topcoat of Sm2Zr2O7 and Sm2Zr2O7/YSZ performed a thermal cycles of 35 and 60 separately under the test temperature of 1100°C. The thermally grown oxide at the topcoat–bondcoat interface was also the major factors that lead to the coating failure on thermal cycling at about 1100°C.

Sign in / Sign up

Export Citation Format

Share Document