Evaluation of CeSZ Thermal Barrier Coatings for Diesels

2000 ◽  
Author(s):  
P.J. Huang ◽  
J.J. Swab ◽  
P.J. Patel ◽  
W.S. Chu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Barrier Coatings ◽  
Coefficient Of Thermal Expansion ◽  
Fuel Efficiency ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Mechanical And Thermal Properties ◽  
Barrier Coatings ◽  
Spray Process

Abstract The development of thermal barrier coatings (TBCs) for diesel engines has been driven by the potential improvements in engine power and fuel efficiency that TBCs represent. TBCs have been employed for many years to reduce corrosion of valves and pistons because of their high temperature durability and thermal insulative properties. There are research programs to improve TBCs wear resistance to allow for its use in tribologically intensive areas of the engine. This paper will present results from tribological tests of ceria stabilized zirconia (CeSZ). The CeSZ was applied by atmospheric plasma spray process. Various mechanical and thermal properties were measured including wear, coefficient of thermal expansion, thermal conductivity, and microhardness. The results show the potential use of CeSZ in wear sensitive applications in diesel applications. Keywords: Thermal Barrier Coating, Diesel Engine, Wear, Thermal Conductivity, and Thermal Expansion

Thermal Conductivity Prediction for Thermal Barrier Coatings

2010 ◽  
Author(s):  
Monica B. Silva ◽  
S. M. Guo ◽  
Patrick F. Mensah ◽  
Ravinder Diwan
Keyword(s):  
Thermal Conductivity ◽  
Thermal Barrier Coatings ◽  
Volume Fraction ◽  
Mercury Porosimetry ◽  
Laser Flash ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Interfacial Resistance ◽  
Barrier Coatings ◽  
Spray Process

Thermal barrier coatings (TBCs) are used in gas turbine engines to achieve a higher working temperature and thus lead to a better efficiency. Yttria-Stabilized-Zirconia (YSZ), a material with low thermal conductivity, is commonly used as the TBC top coat to provide the thermal barrier effect. In this paper, an analytical model is proposed to estimate the effective thermal conductivity of the TBCs based on the microstructures. This model includes the micro structure details, such as grain size, pore size, volume fraction of pores, and the interfacial resistance. To validate the model, two sets of TBC samples were fabricated and tested for thermal conductivity and associated microstructures. The first set of samples were disk shaped YSZ-Al2O3 samples fabricated using a pressing machine. The YSZ-Al2O3 powder mixture was 0, 1, 2, 3, 4 and 5 wt% Al2O3/YSZ powder ratio. The second set of samples were fabricated by Atmospheric Plasma Spray process for two different microstructure configurations, standard (STD) and vertically cracked (VC), at two different thicknesses, 400 and 700 urn respectively. A laser flash system was used to measure the thermal conductivity of the coatings. Experiments were performed over the temperature range from 100°C to 800°C. The porosity of the YSZ samples was measured using a mercury porosimetry analyzer, POREMASTER 33 system. A Scanning Electron Microscope (SEM) was used to study the microstructure of the samples. It is observed that the microstructure and the porosity are directly linked with the thermal conductivity values. The relationship of the properties to the real microstructure determines the validity of the proposed model.

scholarly journals Research on Thermal Stability and Properties of Ca3ZrSi2O9 as Potential T/EBC Materials

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 583
Author(s):  
Yangyang Pan ◽  
Bo Liang ◽  
Yaran Niu ◽  
Dijuan Han ◽  
Dongdong Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Fracture Toughness ◽  
Room Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Mechanical And Thermal Properties ◽  
Self Healing ◽  
Barrier Coating

In this study, a new coating material for thermal barrier coating (TBC) or environment barrier coating (EBC) application, Ca3ZrSi2O9 (CZSO), was synthesized and prepared by atmospheric plasma spray (APS) technology. The evolution of the phases and microstructures of the coatings with different thermal-aged were characterized by XRD, XRF, EDS and SEM, respectively. The thermal stability was measured by TG-DTA and DSC. The mechanical and thermal properties, including Vickers hardness (HV), fracture toughness (KIC), thermal conductivity () and coefficient of thermal expansion (CTE) were focused on. It was found that the as-sprayed CZSO coating contained amorphous phase. Crystalline transformation happened at 900–960 ∘C and no mass changes took place from room temperature (RT) to 1300 ∘C. The phenomena of microcrack self-healing and composition uniformity were observed during thermal aging. The of coating was very low at about 0.57–0.80 Wm−1K−1 in 200–1200 ∘C. The combined properties indicated that the CZSO coating might be a potential T/EBC material.

Design, Preparation and Thermal Properties of (La0.4Sm0.5Yb0.1)2Zr2O7 Ceramic for Thermal Barrier Coatings

2012 ◽  
Vol 512-515 ◽  
pp. 469-473 ◽  
Author(s):  
L. Liu ◽  
Z. Ma ◽  
F.C. Wang ◽  
Q. Xu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Rare Earth ◽  
Thermal Expansion Coefficient ◽  
Thermal Barrier Coatings ◽  
Expansion Coefficient ◽  
Phonon Transport ◽  
Thermal Barrier ◽  
Barrier Coatings

According to the theory of phonon transport and thermal expansion, a new complex rare-earth zirconate ceramic (La0.4Sm0.5Yb0.1)2Zr2O7, with low thermal conductivity and high thermal expansion coefficient, has been designed by doping proper ions at A sites. The complex rare-earth zirconate (La0.4Sm0.5Yb0.1)2Zr2O7 powder for thermal barrier coatings (TBCs) was synthesized by coprecipitation-calcination method. The phase, microstructure and thermal properties of the new material were investigated. The results revealed that single phase (La0.4Sm0.5Yb0.1)2Zr2O7 with pyrochlore structure was synthesized. The thermal conductivity and the thermal expansion coefficient of the designed complex rare-earth zirconate ceramic is about 1.3W/m•K and 10.5×10-6/K, respectively. These results imply that (La0.4Sm0.5Yb0.1)2Zr2O7 can be explored as the candidate material for the ceramic layer in TBCs system.

Thermophysical Properties of Samarium-Cerium Oxide for Thermal Barrier Coatings Application

2007 ◽  
Vol 336-338 ◽  
pp. 1773-1775 ◽  
Author(s):  
Chun Lei Wan ◽  
Wei Pan ◽  
Zhi Xue Qu ◽  
Ye Xia Qin
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Barrier Coatings ◽  
Thermophysical Properties ◽  
Ceramic Coating ◽  
Fluorite Structure ◽  
Yttria Stabilized Zirconia ◽  
Thermal Barrier ◽  
Stabilized Zirconia ◽  
Barrier Coatings

Sm0.4Ce0.6O1.8 specimen with a defective fluorite structure was synthesized and its thermophysical properties were characterized for thermal barrier coatings (TBCs) application. At high temperature, Sm0.4Ce0.6O1.8 exhibited much lower thermal conductivity than 7wt% yttria-stabilized zirconia (7YSZ)-the commonly used composition in current TBCs. Sm0.4Ce0.6O1.8 also possessed large thermal expansion coefficient, which could help reduce the thermal mismatch between the ceramic coating and bond coat.

A Promising LaSmZr2O7 Ceramic with Pyrochlore Structure for Thermal Barrier Coatings

2008 ◽  
Vol 368-372 ◽  
pp. 1328-1330
Author(s):  
Qiang Xu ◽  
Wei Pan ◽  
Chun Lei Wan ◽  
Long Hao Qi ◽  
He Zhuo Miao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Thermal Barrier Coatings ◽  
Expansion Coefficient ◽  
Pyrochlore Structure ◽  
Solid State Reaction Method ◽  
Rare Earth Ions ◽  
Thermal Barrier ◽  
Barrier Coatings

Based on La2Zr2O7 ceramic for thermal barrier coatings, LaSmZr2O7 ceramic doped with samarium ion was successfully prepared using solid state reaction method. The pellets were sintered at 1600°C for 10 hours in air. The phase structure, thermal conductivity and thermal expansion coefficient of LaSmZr2O7 ceramic and La2Zr2O7 ceramic were measured by XRD, laser-flash device, high-temperature dilatometry, respectively. The results show that the crystal structure of LaSmZr2O7 ceramic is not affected by the doped samarium ion in the zirconium lattice. The thermophysical results show that the thermal conductivity of the LaSmZr2O7 ceramic is lower than that of La2Zr2O7 ceramic, while the thermal expansion coefficient is higher than that of La2Zr2O7 ceramic. These results indicate that LaSmZr2O7 ceramic or Ln2Zr2O7 ceramics doped with other rare earth ions could be candidate materials for future thermal barrier coatings.

Preparation and Thermophysical Properties of (La0.4Sm0.5Yb0.1)2(Zr0.7Ce0.3)2O7 Ceramic for Thermal Barrier Coatings

2008 ◽  
Vol 368-372 ◽  
pp. 1334-1336
Author(s):  
Ling Liu ◽  
Qiang Xu ◽  
Fu Chi Wang ◽  
Hong Song Zhang
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Rare Earth ◽  
Phase Composition ◽  
Thermal Barrier Coatings ◽  
Thermophysical Properties ◽  
Single Phase ◽  
Pyrochlore Structure ◽  
Thermal Barrier ◽  
Barrier Coatings

A complex rare-earth zirconate (La0.4Sm0.5Yb0.1)2(Zr0.7Ce0.3)2O7 powder for thermal barrier coatings (TBCs) was synthesized by coprecipitation method. The phase composition, microstructure and the thermophysical properties were investigated. XRD results revealed that single phase (La0.4Sm0.5Yb0.1)2(Zr0.7Ce0.3)2O7 with pyrochlore structure was prepared and the SEM result showed that the microstructure of the product was dense and no other phases existed among the particles. With the temperature increasing, the thermal expansion coefficient (CTE) of the ceramic increased, while the thermal conductivity decreased. The results indicated that CTE of the ceramic was slightly higher than that of La2Zr2O7 and the thermal conductivity of the ceramic was lower than that of La2Zr2O7. These results imply that (La0.4Sm0.5Yb0.1)2(Zr0.7Ce0.3)2O7 can be explored as the candidate material for the ceramic layer in TBCs system.

scholarly journals Thermal Conductivity of Multi-Sized Porous Thermal Barrier Coatings at Micro and Nano Scales after Long-Term Service at High Temperatures

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1183
Author(s):  
Pei-Hu Gao ◽  
Sheng-Cong Zeng ◽  
Can Jin ◽  
Bo Zhang ◽  
Bai-Yang Chen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Porous Structure ◽  
Thermal Barrier Coatings ◽  
Laser Flash ◽  
Physical Models ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Barrier Coatings

Thermal barrier coatings with multi-sized porous structure at micro and nano scales were prepared with hollow spherical YSZ powders and polypropylene powders through atmospheric plasma spraying. The thermal conductivities of the multi-sized thermal barrier coatings after a long-term serving at high temperature were tested through laser flash heating method. Meanwhile, the physical models of thermal barrier coatings with multi-sized porous structure at micro and nano scales were constructed through Ansys Workbench. The evolutions of thermal conductivity of thermal barrier coatings with multi-sized pores after long-term service at 1100 °C were investigated through computation. It was found that the thermal conductivity of the coating increased with the extension of the serving time. When the serving time reached 60 days, the thermal conductivity of the coating tended to be stable and close to the compacted bulk. The computational results were consistent with the tested ones, which could be helpful to explain the thermal conducting evolution in thermal barrier coatings with multi-sized porous structure at nano and micro scales after long-term serving at high temperature.

Advances in Low Thermal Conductivity Materials for Thermal Barrier Coatings

2021 ◽  
pp. 88-111
Author(s):  
Rafael Vargas-Bernal ◽  
Bárbara Bermúdez-Reyes
Keyword(s):  
Thermal Conductivity ◽  
Thermal Barrier Coatings ◽  
Coefficient Of Thermal Expansion ◽  
Chemical Properties ◽  
Future Research ◽  
Thermal Barrier ◽  
Chemical Compositions ◽  
Barrier Coatings ◽  
Low Thermal Conductivity ◽  
Future Research Directions

One of the areas of research that continue to attract researchers worldwide is the development of thermal barrier coatings (TBCs) especially associated with the design of new ceramic topcoats with low thermal conductivity and a high coefficient of thermal expansion. The purpose of this chapter is to present the advances that have been achieved regarding ceramic topcoats in the last decades, making a historical journey that culminates with the contributions of this decade. The introduction of new crystalline structures and chemical compositions have opened the door to the real possibilities of replacing yttria-stabilized zirconia (YSZ) to ensure the optimal thermomechanical-chemical properties required by TBCs. Future research directions associated with this topic are also provided.

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