Thermal Diffusivity/Microstructure Relationship in Y-PSZ Thermal Barrier Coatings

Cernuschi, F.; Bianchi, Paolo Emilio; Leoni, Matteo; Scardi, Paolo

doi:10.1361/105996399770350629

Cited by 128 publications

(64 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Attention is focussed here on two-component systems, in which the second component is in the form of gas-filled pores. Such systems can be modelled as incorporating randomly-distributed pores [3][4][5][6], contact resistance [7][8][9] or periodic structures [10,11]. Randomly-distributed inclusions, at dilute concentrations, have been modelled, assuming them to be non-interacting [4,5], whereas, for higher porosity levels, self-consistent [12,13] and effective medium [3,14] models have been developed.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work

2009

View full text Add to dashboard Cite

A review is presented of how heat transfer takes place in plasma sprayed (zirconia-based) thermal barrier coatings (TBCs) during operation of gas turbines. These characteristics of TBCs are naturally of central importance to their function. Current state-of-the-art TBCs have relatively high levels of porosity (~15%) and the pore architecture (ie its morphology, connectivity and scale) has a strong influence on the heat flow. Contributions from convective, conductive and radiative heat transfer are considered, under a range of operating conditions, and the characteristics are illustrated with experimental data and modelling predictions. In fact, convective heat flow within TBCs usually makes a negligible contribution to the overall heat transfer through the coating, although what might be described as convection can be important if there are gross through-thickness defects such as segmentation cracks. Radiative heat transfer, on the other hand, can be significant within TBCs, depending on temperature and radiation scattering lengths, which in turn are sensitive to the grain structure and the pore architecture. Under most conditions of current interest, conductive heat transfer is largely predominant. However, it is not only conduction through solid ceramic that is important. Depending on the pore architecture, conduction through gas in the pores can play a significant role, particularly at the high gas pressures typically acting in gas turbines (although rarely applied in laboratory measurements of conductivity). The durability of the pore structure under service conditions is also of importance, and this review covers some recent work on how the pore architecture, and hence the conductivity, is affected by sintering phenomena. Some information is presented concerning the areas in which research and development work needs to be focussed if improvements in coating performance are to be achieved.

show abstract

Section: Introductionmentioning

confidence: 99%

Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work

2009

View full text Add to dashboard Cite

show abstract

“…[1] There are two major reasons for the failure of the conventional TBCs. The first one is the oxidation of the MCrAlY bond coat at elevated temperatures.…”

mentioning

confidence: 99%

Hollow Fibers of Lanthanum Cerium Oxide Prepared by Electrospinning

et al. 2007

View full text Add to dashboard Cite

“…The nature of the cracks can have significant influence on the properties of the coating. For example, it was observed that the planar defects parallel to the substrate are more influential on mechanical properties (Ref 8) as well as thermal diffusivity (Ref 8,9), than the total porosity. Vickers microhardness test using 300 g loads for 15 s was done on selected samples.…”

Section: Methodsmentioning

confidence: 99%

Effective Parameters in Axial Injection Suspension Plasma Spray Process of Alumina-Zirconia Ceramics

et al. 2008

View full text Add to dashboard Cite

Suspension plasma spray (SPS) is a novel process for producing nano-structured coatings with metastable phases using significantly smaller particles as compared to conventional thermal spraying. Considering the complexity of the system there is an extensive need to better understand the relationship between plasma spray conditions and resulting coating microstructure and defects. In this study, an alumina/ 8 wt.% yttria-stabilized zirconia was deposited by axial injection SPS process. The effects of principal deposition parameters on the microstructural features are evaluated using the Taguchi design of experiment. The microstructural features include microcracks, porosities, and deposition rate. To better understand the role of the spray parameters, in-flight particle characteristics, i.e., temperature and velocity were also measured. The role of the porosity in this multicomponent structure is studied as well.The results indicate that thermal diffusivity of the coatings, an important property for potential thermal barrier applications, is barely affected by the changes in porosity content.

show abstract

Thermal Diffusivity/Microstructure Relationship in Y-PSZ Thermal Barrier Coatings

Cited by 128 publications

References 8 publications

Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work

Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work

Hollow Fibers of Lanthanum Cerium Oxide Prepared by Electrospinning

Effective Parameters in Axial Injection Suspension Plasma Spray Process of Alumina-Zirconia Ceramics

Contact Info

Product

Resources

About