scholarly journals High Temperature Stability and Thermal Cycling Life of Plasma Sprayed Nanostructured Thermal Barrier Coating with Low Impurity Content

2018 ◽  
Author(s):  
Tao Yuan ◽  
Qing He ◽  
Yufen Lv ◽  
Han Zou
Keyword(s):  
High Temperature ◽  
Thermal Cycling ◽  
Impurity Content ◽  
Temperature Stability ◽  
Thermal Barrier ◽  
High Temperature Stability ◽  
Barrier Coating ◽  
Plasma Sprayed ◽  
Nanostructured Thermal Barrier Coating ◽  
Cycling Life

Microstructural Evolution of GdZ and DySZ Based EB-PVD TBC Systems After Thermal Cycling at High Temperature

2013 ◽  
Vol 135 (10) ◽  
Author(s):  
Ahmed Umar Munawar ◽  
Uwe Schulz ◽  
Giovanni Cerri
Keyword(s):  
High Temperature ◽  
Thermal Cycling ◽  
Physical Vapor Deposition ◽  
Temperature Stability ◽  
Double Layers ◽  
Inlet Temperature ◽  
High Temperature Stability ◽  
Turbine Inlet Temperature ◽  
Barrier Coating ◽  
Tbc Systems

Lower thermal conductivity and high temperature stability are the two properties which are highly desired from ceramic top coat materials in thermal barrier coating (TBC) systems. Gadolinium zirconate, Gd2Zr2O7 (GdZ) and dyprosia stabilized zirconia (DySZ) are two of the candidate materials with such properties and consequently the TBC system would be able to work at higher turbine inlet temperature (TIT) or the lifetime can be increased. In the present study, lifetime measurements are done for single and double layered electron beam physical vapor deposition (EB-PVD) GdZ and DySZ samples by thermal-cycling tests. The double layered TBCs consisted of a thin 7YSZ layer and, on top, the new candidate material. Both single and double layered samples of GdZ and DySZ have shown similar or better lifetimes than the standard 7YSZ samples. However, single layered TBCs showed better lifetime results than the respective double layers. In this study, changes in the microstructure, diffusion of elements and sintering of the TBC materials with aging are observed.

Revolutionary High-entropy Zr-Y-Yb-Ta-Nb-O Oxides for Next Generation Thermal Barrier Coating Applications

2021 ◽  
Author(s):  
Yao Yao ◽  
Fan Yang ◽  
Xiaofeng Zhao ◽  
Ping Xiao
Keyword(s):  
High Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Temperature Stability ◽  
Thermal Barrier ◽  
Next Generation ◽  
Transformation Toughening ◽  
High Temperature Stability ◽  
High Entropy ◽  
Barrier Coating ◽  
Phase Transformation Toughening

Abstract We report a revolutionary ceramic material with exceptional high temperature stability and superior thermo-mechanical properties for next generation thermal barrier coatings (TBCs) for aeroengines. The multicomponent oxides (Zr1 − 4xYxYbxTaxNbxO2) designed via a high entropy concept could exhibit a double tetragonal phase. The optimized composition breaks the limitation of intrinsic brittleness in previously reported TBC candidate materials and shows a superior toughness up to ~ 4.59 MPa m1/2 due to ferroelastic and phase transformation toughening mechanisms. It also shows a remarkable high temperature stability at 1600 ºC, which is almost 400 ºC higher than the state-of-the-art yttria stabilized zirconia TBC material. In addition, it also exhibits a significantly lower thermal conductivity (~ 1.37 W∙m− 1∙K− 1 at 900 ºC) and a higher coefficient of thermal expansion (~ 11.3 × 10− 6 K− 1 at 1000 ºC), as well as excellent corrosion resistance to molten silicate (~ 2.9 µm/h at 1300 ºC). This work provides a new approach to design ceramics by extending the high-entropy concept to both medium-entropy and high-entropy compositions searching for multifunctional properties.

Sintering Behavior of Plasma-Sprayed Sm2Zr2O7 Coating

2010 ◽  
Author(s):  
Jianhua Yu ◽  
Huayu Zhao ◽  
Shunyan Tao ◽  
Xiaming Zhou ◽  
Chuanxian Ding
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
High Temperature ◽  
Thermal Expansion Coefficient ◽  
Thermal Barrier Coating ◽  
Expansion Coefficient ◽  
Sintering Behavior ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Plasma Sprayed

Plasma-sprayed thermal barrier coating (TBC) systems are widely used in gas turbine blades to increase turbine entry temperature (TET) and better efficiency. Yttria stabilized zirconia (YSZ) has been the conventional thermal barrier coating material because of its low thermal conductivity, relative high thermal expansion coefficient and good corrosion resistance. However the YSZ coatings can hardly fulfill the harsh requirements in future for higher reliability and the lower thermal conductivity at higher temperatures. Among the interesting TBC candidates, materials with pyrochlore structure show promising thermo-physical properties for use at temperatures exceeding 1200 °C. Sm2Zr2O7 bulk material does not only have high temperature stability, sintering resistance but also lower thermal conductivity and higher thermal expansion coefficient. The sintering characteristics of ceramic thermal barrier coatings under high temperature conditions are complex phenomena. In this paper, samarium zirconate (Sm2Zr2O7, SZ) powder and coatings were prepared by solid state reaction and atmosphere plasma spraying process, respectively. The microstructure development of coatings derived from sintering after heat-treated at 1200–1500 °C for 50 h have been investigated. The microstructure was examined by scanning electron microscopy (SEM) and the grain growth was analyzed in this paper as well.

Finite Element Analysis of Temperature Characteristicon the Pressure Sensor Based on the Shell of Piezo Gauge

2010 ◽  
Vol 156-157 ◽  
pp. 117-122
Author(s):  
Xin E. Li ◽  
Jing Zu ◽  
Peng Xu
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Thermal Barrier Coating ◽  
Temperature Stability ◽  
Chamber Pressure ◽  
Thermal Barrier ◽  
Element Analysis ◽  
Temperature Characteristics ◽  
Barrier Coating ◽  
Novel Method

When the gun chamber pressure is tested, its instantaneous high temperature up to 3000 , Sensor directly touches the high temperature gas. According to this special use environment, A novel method is proposed in this paper: the thermal barrier coating (TBC) is added to protect the sensor against its thermal deformity. And temperature characteristics of the sensor with TBC are analyzed through finite element. finally, its temperature characteristics were experimentally tested. Results show that the thermal barrier coating plaied heat insulation role, temperature stability of the sensor is good.

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.

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