scholarly journals Synthesis, Characterization and Thermal Diffusivity of Holmium and Praseodymium Zirconates

2016 ◽  
Vol 61 (2) ◽  
pp. 1249-1254 ◽  
Author(s):  
M. Stopyra ◽  
D. Niemiec ◽  
G. Moskal
Keyword(s):  
Thermal Diffusivity ◽  
Thermal Barrier Coatings ◽  
Single Phase ◽  
Fluorite Structure ◽  
Thermal Barrier ◽  
Complex Method ◽  
Insulation Layer ◽  
Barrier Coatings ◽  
Decomposition Of Solid Solution ◽  
Insulating Properties

Abstract A2B2O7 oxides with pyrochlore or defected fluorite structure are among the most promising candidates for insulation layer material in thermal barrier coatings. The present paper presents the procedure of synthesis of holmium zirconate Ho2Zr2O7 and praseodymium zirconate Pr2Zr2O7 via Polymerized-Complex Method (PCM). Thermal analysis of precursor revealed that after calcination at relatively low temperature (700°C) fine-crystalline, single-phase material is obtained. Thermal diffusivity was measured in temperature range 25-200°C, Ho2Zr2O7 exhibits lower thermal diffusivity than Pr2Zr2O7. Additionally, PrHoZr2O7 was synthesized. The powder in as-calcined condition is single-phase, but during the sintering decomposition of solid solution took place and Ho-rich phase precipitated. This material exhibited the best insulating properties among the tested ones.

scholarly journals The Numerical Modeling of Thermal Stress Distribution in Thermal Barrier Coatings

2017 ◽  
Vol 62 (3) ◽  
pp. 1433-1437
Author(s):  
A. Jasik
Keyword(s):  
Thermal Stress ◽  
Stress Distribution ◽  
Thermal Barrier Coatings ◽  
Bond Coat ◽  
Thermal Spraying ◽  
Ceramic Coatings ◽  
Thermal Barrier ◽  
Insulation Layer ◽  
Barrier Coatings ◽  
Thermal Stress Distribution

Abstract The paper presents the results of numerical calculations of temperature and thermal stress distribution in thermal barrier coatings deposited by thermal spraying process on the nickel based superalloy. An assumption was made to apply conventional zirconium oxide modified with yttrium oxide (8YSZ) and apply pyrochlore type material with formula La2Zr2O7. The bond coat was made of NiCoCrAlY. Analysis of the distribution of temperature and stresses in ceramic coatings of different thicknesses was performed in the function of bond-coat thickness and the type of ceramic insulation layer. It was revealed that the thickness of NiCrAlY bond-coat has not significant influence on the stress distribution, but there is relatively strong effect on temperature level. The most important factor influenced on stress distribution in TBC system is related with type and properties of ceramic insulation layer.

Comparison of Single-Phase and Two-Phase Composite Thermal Barrier Coatings with Equal Total Rare-Earth Content

2018 ◽  
Vol 27 (4) ◽  
pp. 556-565 ◽  
Author(s):  
Amarendra K. Rai ◽  
Michael P. Schmitt ◽  
Mitchell R. Dorfman ◽  
Dongming Zhu ◽  
Douglas E. Wolfe
Keyword(s):  
Rare Earth ◽  
Thermal Barrier Coatings ◽  
Single Phase ◽  
Thermal Barrier ◽  
Two Phase ◽  
Barrier Coatings ◽  
Rare Earth Content

Rare-Earth Zirconate Ceramics with Fluorite Structure for Thermal Barrier Coatings

2006 ◽  
Vol 89 (1) ◽  
pp. 340-342 ◽  
Author(s):  
Qiang Xu ◽  
Wei Pan ◽  
Jingdong Wang ◽  
Chunlei Wan ◽  
Longhao Qi ◽  
...  
Keyword(s):  
Rare Earth ◽  
Thermal Barrier Coatings ◽  
Fluorite Structure ◽  
Thermal Barrier ◽  
Barrier Coatings

Thermal Barrier Coatings on the Base of Samarium Zirconates

2018 ◽  
pp. 79-106
Author(s):  
Sebastian Oliwer Jucha ◽  
Grzegorz Jan Moskal
Keyword(s):  
Rare Earth ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Insulation Layer ◽  
Barrier Coatings ◽  
Alternative Material ◽  
Static Oxidation ◽  
Tbc Systems ◽  
Samarium Zirconate

The zirconates of rare earth elements, such as Sm2Zr2O7, can be an alternative material for zirconia modified by yttria (8YSZ) usually used as an insulation layer in thermal barrier coatings (TBC) systems. This chapter describes the morphology of feedstock zirconate powder, internal morphology and selected properties of different samarium zirconate TBC systems. These included: composite TBC coatings of Sm2Zr2O7 + 8YSZ type with different ratio of both used to coatings deposition powders (25/75, 50/50 and 75/25) as well as the TBC of double ceramic layer (DCL) type with an 8YSZ internal layer and an outer layer of Sm2Zr2O7 type, and a monolayer TBC based on Sm2Zr2O7. Another presented subject is related to the oxidation resistance of TBC systems during static oxidation test at temperature 1100°C. In this case, the special emphasis was taken on the characterization of thermally grown oxides (TGO) zone thickness where the most important phenomena related with overall live-time of TBC systems usually take place.

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.

scholarly journals Optimal parameterization in the measurements of the thermal diffusivity of thermal barrier coatings

2007 ◽  
Vol 11 (1) ◽  
pp. 137-156
Author(s):  
Nenad Milosevic
Keyword(s):  
Thermal Diffusivity ◽  
Thermal Barrier Coatings ◽  
Steel Substrate ◽  
Thermal Contact ◽  
Copper Substrate ◽  
Estimation Procedure ◽  
Laser Flash ◽  
Flash Method ◽  
Thermal Barrier ◽  
Barrier Coatings

The paper presents an estimation procedure for the measurement of the thermal diffusivity of thermal barrier coatings deposited on thermal conductive substrates using the laser flash method when the thermal contact resistance between the coating and substrate is unknown. The procedure is based on the application of the optimal parameterization technique and Gauss minimization algorithm. It has been applied on the experimental data obtained by using two different samples, one made of PTFE (polytetrafluoroethylene) coating deposited on a stainless steel substrate and the other made of PVC (polyvinylchloride) deposited on a copper substrate. .

Sign in / Sign up

Export Citation Format

Share Document