Layered, composite, and doped thermal barrier coatings exposed to sand laden flows within a gas turbine engine: Microstructural evolution, mechanical properties, and CMAS deposition

2018 ◽  
Vol 349 ◽  
pp. 1107-1116 ◽  
Author(s):  
Andy Nieto ◽  
Michael Walock ◽  
Anindya Ghoshal ◽  
Dongming Zhu ◽  
William Gamble ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Microstructural Evolution ◽  
Gas Turbine Engine ◽  
Layered Composite ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Turbine Engine

Synchrotron X-Ray Diffraction to Quantify In-Situ Strain on Rare-Earth Doped Yttria-Stabilized Zirconia Thermal Barrier Coatings

2021 ◽  
Author(s):  
Quentin Fouliard ◽  
Johnathan Hernandez ◽  
Hossein Ebrahimi ◽  
Khanh Vo ◽  
Ranajay Ghosh ◽  
...  
Keyword(s):  
Rare Earth ◽  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Gas Turbine Engine ◽  
Temperature Sensing ◽  
Thermal Barrier ◽  
X Ray Diffraction ◽  
Barrier Coatings ◽  
Turbine Engine ◽  
X Ray

Abstract The recent advancement in multifunctional thermal barrier coatings (TBCs) for temperature sensing or defect monitoring has gained interest over the past decade as they have shown great potential for optimized engine operation with higher efficiency, reduced fuel consumption and maintenance costs. Specifically, sensor coatings containing luminescent ions enable materials monitoring using integrated spectral characteristics. While facilitating sensing capabilities, luminescent rare-earth dopants ideally present minimal intrusiveness for the thermal barrier coating. However, the effects of rare-earth dopant addition on thermomechanical and thermochemical properties remain unclear. Our study intends to fill this knowledge gap by characterizing coatings’ internal thermomechnical properties under realistic gas turbine engine operating temperatures. In this work, TBC configurations including industry standard coatings and sensor coatings were compared to quantify dopant intrusiveness. The TBC configurations have been characterized using high-energy synchrotron X-ray diffraction while being heated up to gas turbine engine temperatures. The TBC samples have been subjected to a single cycle thermal load with multiple ramps and holds during XRD data collection. Depth-resolved XRD was used to obtain the 2D diffraction patterns corresponding to each depth location for the determination of strain distributions along the TBCs. Internal strains and stresses acting through the coatings were quantified mostly highlighting that there is negligible variation between the standard and novel sensor coatings. Thus, the thermal response at high temperature remains unaffected with addition of luminescent dopants. This evaluation of novel coating configurations provides valuable insight for future safe implementation of these temperature sensing coatings without performance reductions.

Study on Improvement of Oxide Layer and Properties of Plasma Sprayed Alumina in Thermal Barrier Coatings

2007 ◽  
Vol 127 ◽  
pp. 313-318 ◽  
Author(s):  
Akira Kobayashi ◽  
G. Shanmugavelayutham ◽  
S. Yano
Keyword(s):  
Mechanical Properties ◽  
Oxidation Resistance ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Potential Candidate ◽  
Low Oxygen ◽  
Temperature Oxidation ◽  
Barrier Coatings ◽  
Turbine Engine ◽  
Α Al2o3

Thermal barrier coatings (TBC) have been used to improve the efficiency of turbine engine by providing the capability to sustain significant temperature gradient across the coating. TBC failure occurs easily at the interface between the metallic bondcoat and topcoat. Alumina was proposed as a potential candidate as an interlayer to improve the oxidation resistance of thermal barrier coating due to its low oxygen diffusivity against the harsh environment. The mechanical properties, thermal behaviour and high temperature oxidation resistance of the coatings formed by gas tunnel type plasma spraying were investigated in this study. The results showed that this system exhibits the improvement of mechanical properties of the coating and oxidation resistance. This interlayer is preferred in order to minimize the detrimental effect of phase transformation of γ- Al2O3 to α-Al2O3.

Near Net-Shape Forming of Thermal Barrier Coated Components for Gas Turbine Engine Applications

1998 ◽  
Author(s):  
G.E. Kim ◽  
P.G. Tsantrizos ◽  
S. Grenier ◽  
A. Cavasin ◽  
T. Brzezinski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Gas Turbine ◽  
Bond Coat ◽  
Gas Turbine Engine ◽  
Thermal Barrier ◽  
Forming Process ◽  
Turbine Engine ◽  
Near Net Shape ◽  
Net Shape Forming

Abstract PyroGenesis Inc. has developed a unique Vacuum Plasma Spraying (VPS) near-net-shape forming process for the production of multilayered free-standing components. Initial evaluation on the feasibility of applying this process for the production of gas turbine engine components has been performed. The VPS near-net-shape forming process consists of: selecting an appropriate mold material; preconditioning of mold surface ; depositing metallic, ceramic, or composite layers ; and removing mold from the spray-formed structure. The near-net-shape components are heat treated to improve their mechanical properties. A suitable heat treatment cycle was developed for the VPS-applied superalloy. Much of the recent improvements in gas turbine engine performance has been attributed to the introduction of thermal barrier coatings (TBC) for superalloy components. There exist, however, some limitations in current fabrication methods for closed hot-section components: less than ideal coating quality; welding; limited choice of superalloy material; etc... PyroGenesis has used VPS near-net-shape forming to fabricate closed components with an yttria-stabilized-zirconia inner layer, CoNiCrA1Y bond coat, and IN-738LC outer layer. The results from the initial study demonstrate the feasibility of producing near-net-shape components with good coating structures, superior superalloy materials, and the absence welds. The mold was reusable after minor surface conditioning. The TBC showed uniform thickness and microstructure with a smooth surface finish. The bond coat and structural superalloy layers were very dense with no signs of oxidation at the interface. After heat treatment, the mechanical properties of the IN-738LC compare favourably to cast materials.

scholarly journals Microstructure Based Material-Sand Particulate Interactions and Assessment of Coatings for High Temperature Turbine Blades

2017 ◽  
Author(s):  
Muthuvel Murugan ◽  
Anindya Ghoshal ◽  
Michael Walock ◽  
Andy Nieto ◽  
Luis Bravo ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Thermal Barrier Coatings ◽  
Turbine Blades ◽  
Turbine Engines ◽  
Thermal Barrier ◽  
Gas Turbine Engines ◽  
Barrier Coatings ◽  
Turbine Engine

Gas turbine engines for military/commercial fixed-wing and rotary wing aircraft use thermal barrier coatings in the high-temperature sections of the engine for improved efficiency and power. The desire to further make improvements in gas turbine engine efficiency and high power-density is driving the research and development of thermal barrier coatings with the goal of improving their tolerance to fine foreign particulates that may be contained in the intake air. Both commercial and military aircraft engines often are required to operate over sandy regions such as in the middle-east nations, as well as over volcanic zones. For rotorcraft gas turbine engines, the sand ingestion is adverse during take-off, hovering near ground, and landing conditions. Although most of the rotorcraft gas turbine engines are fitted with inlet particle separators, they are not 100% efficient in filtering fine sand particles of size 75 microns or below. The presence of these fine solid particles in the working fluid medium has an adverse effect on the durability of turbine blade thermal barrier coatings and overall performance of the engine. Typical turbine blade damage includes blade coating wear, sand glazing, Calcia-Magnesia-Alumina-Silicate (CMAS) attack, oxidation, and plugged cooling holes, all of which can cause rapid performance deterioration including loss of aircraft. The objective of this research is to understand the fine particle interactions with typical turbine blade ceramic coatings at the microstructure level. Finite-element based microstructure modeling and analysis has been performed to investigate particle-surface interactions, and restitution characteristics. Experimentally, a set of tailored thermal barrier coatings and surface treatments were down-selected through hot burner rig tests and then applied to first stage nozzle vanes of the gas generator turbine of a typical rotorcraft gas turbine engine. Laser Doppler velocity measurements were performed during hot burner rig testing to determine sand particle incoming velocities and their rebound characteristics upon impact on coated material targets. Further, engine sand ingestion tests were carried out to test the CMAS tolerance of the coated nozzle vanes. The findings from this on-going collaborative research to develop the next-gen sand tolerant coatings for turbine blades are presented in this paper.

scholarly journals Erosion Performance of Atmospheric Plasma Sprayed Thermal Barrier Coatings with Diverse Porosity Levels

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 86
Author(s):  
Satyapal Mahade ◽  
Abhilash Venkat ◽  
Nicholas Curry ◽  
Matthias Leitner ◽  
Shrikant Joshi
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Sem Analysis ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Turbine Engine ◽  
Plasma Sprayed ◽  
Engine Components ◽  
Micro Indentation

Thermal barrier coatings (TBCs) prolong the durability of gas turbine engine components and enable them to operate at high temperature. Several degradation mechanisms limit the durability of TBCs during their service. Since the atmospheric plasma spray (APS) processed 7–8 wt.% yttria stabilized zirconia (YSZ) TBCs widely utilized for gas turbine applications are susceptible to erosion damage, this work aims to evaluate the influence of their porosity levels on erosion behavior. Eight different APS TBCs were produced from 3 different spray powders with porosity ranging from 14% to 24%. The as-deposited TBCs were examined by SEM analysis. A licensed software was used to quantify the different microstructural features. Mechanical properties of the as-deposited TBCs were evaluated using micro-indentation technique. The as-deposited TBCs were subjected to erosion tests at different angles of erodent impact and their erosion performance was evaluated. Based on the results, microstructure-mechanical property-erosion performance was correlated. Findings from this work provide new insights into the microstructural features desired for improved erosion performance of APS deposited YSZ TBCs.

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