Progression in Non-Destructive Spallation Prediction and Elevated Temperature Mechanical Property Evaluation of Thermal Barrier Coating Systems by Use of a Spherical Micro-Indentation Method

Tannenbaum, J. M.

doi:10.33915/etd.3054

Cited by 4 publications

(15 citation statements)

References 96 publications

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“…To determine the Young's modulus values of the areas of TBC with varying amount of deposition, a table top load-based multiple-partial unloading micro-indentation system is used. Studies by Tannenbaum [8] and Otunyo [9] have used the micro-indentation systems at WVU to measure the Young's modulus of the TBC systems. Their studies were able to predict future spallation locations in areas of theYSZ coatings that exhibited increases in surface stiffness.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Syngas Particulate Fly Ash Deposition on the Mechanical Properties of Thermal Barrier Coatings on Simulated Film-Cooled Turbine Vane Components

Luo¹,

Nix²,

Kang³

et al. 2014

IJCCE

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Research is being conducted to study the effects of particulate deposition from contaminants in coal synthesis gas (syngas) on the mechanical properties of thermal barrier coatings (TBC) employed on integrated gasification combined cycle (IGCC) turbine hot section airfoils. West Virginia University (WVU) had been working with US Department of Energy, National Energy Technology Laboratory (NETL) to simulate deposition on the pressure side of an IGCC turbine first stage vane. To model the deposition, coal fly ash was injected into the flow of a combustor facility and deposited onto TBC coated, angled film-cooled test articles in a high pressure (approximately 4 atm) and a high temperature (1560 K) environment. To investigate the interaction between the deposition and the TBC, a load-based multiple-partial unloading micro-indentation technique was used to quantitatively evaluate the mechanical properties of materials. The indentation results showed the Young's Modulus of the ceramic top coat was higher in areas with deposition formation due to the penetration of the fly ash. This corresponds with the reduction of strain tolerance of the 7% yttria-stabilized zirconia (7YSZ) coatings.

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Section: Introductionmentioning

confidence: 99%

“…Table top micro-indentation setup: (i) 3.6 nm Resolution, Physik Instrumente, P-239.9S, 180 μm piezoelectric actuator; (ii) ±0.15% Accuracy, Honeywell, Model 31, 100 lb. load cell; (iii) spherical tungsten carbide (WC) 793.5 μm radius indenter; and (iv) sample stage[8].…”

mentioning

confidence: 99%

Effects of Syngas Particulate Fly Ash Deposition on the Mechanical Properties of Thermal Barrier Coatings on Simulated Film-Cooled Turbine Vane Components

Luo¹,

Nix²,

Kang³

et al. 2014

IJCCE

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“…The in-house made microindentation system is capable of measuring room temperature stiffness response. Indicated in Fig 3.3 is a table top room temperature indentation system comprises of (i) 3.6 nm resolution physik Instrumente P-239.9S 180 μm piezoelectric actuator, (ii) ±0.15% accuracy honeywell (model 31) 100 lb load cell, (iii) spherical tungsten carbide (WC) 750 μm radius indenter, and (iv) specimen stage [120]. For indentation tests, the ODS specimens were polished after thermal cyclic exposure to get the stiffness response on the oxide free surface or directly on the oxide surface to get the stiffness response of the oxide scale and its adhesion property to the ODS alloy it grows on.…”

Section: Microindentation Testingmentioning

confidence: 99%

“…Specifically, for ODS alloy coating with micro-channel cooling system within ODS alloy, it is about 160 °C, but for TBC system it is about 230 °C. This greater temperature drop across the TBC system would induce additional thermal stress within the TBC layer, leading to TBC degradation [120].…”

Section: Temperature Distribution In the Model And Substratementioning

confidence: 99%

“…Additional efforts were also addressed to establish the basis for enhanced stiffness response with extended high temperature cyclic testing of MCB plus ball milled ODS alloy systems in comparison to current/previously developed HVOF ODS alloy coating [154] and thermal barrier coating (TBC) systems [120] as a possible means of implementing these MCB plus ball milled ODS alloys as a structural high temperature coating on turbine blades by implementing microchannel cooling system beneath or within the coating [155]. In a similar test condition of this study, TBC systems [120] showed spallation failure after 400 thermal cycles, whereas oxide scales on MCB plus ball milled ODS alloy specimens were very adherent to the metal matrix without any spallation up to longer thermal cycles, more than 700 cycles.…”

Section: Temperature Distribution In the Model And Substratementioning

confidence: 99%

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Mechanical and Microstructure Study of Nickel-Based ODS Alloys Processed by Mechano-Chemical Bonding and Ball Milling

Amare¹

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Mechanical and Microstructure Study of Nickel-Based ODS Alloys Processed by Mechano-Chemical Bonding and Ball Milling Belachew N. Amare Due to the need to increase the efficiency of modern power plants, land-based gas turbines are designed to operate at high temperature creating harsh environments for structural materials. The elevated turbine inlet temperature directly affects the materials at the hottest sections, which includes combustion chamber, blades, and vanes. Therefore, the hottest sections should satisfy a number of material requirements such as high creep strength, ductility at low temperature, high temperature oxidation and corrosion resistance. Such requirements are nowadays satisfied by implementing superalloys coated by high temperature thermal barrier coating (TBC) systems to protect from high operating temperature required to obtain an increased efficiency. Oxide dispersive strengthened (ODS) alloys are being considered due to their high temperature creep strength, good oxidation and corrosion resistance for high temperature applications in advanced power plants. These alloys operating at high temperature are subjected to different loading systems such as thermal, mechanical, and thermo-mechanical combined loads at operation. Thus, it is critical to study the high temperature mechanical and microstructure properties of such alloys for their structural integrity. The primary objective of this research work is to investigate the mechanical and microstructure properties of nickel-based ODS alloys produced by combined mechano-chemical bonding (MCB) and ball milling subjected to high temperature oxidation, which are expected to be applied for high temperature turbine coating with micro-channel cooling system. Stiffness response and microstructure evaluation of such alloy systems was studied along with their oxidation mechanism and structural integrity through thermal cyclic exposure. Another objective is to analyze the heat transfer of ODS alloy coatings with micro-channel cooling system using finite element analysis (FEA) to determine their feasibility as a stand-alone structural coating. During this project it was found that stiffness response to increase and remain stable to a certain level and reduce at latter stages of thermal cyclic exposure. The predominant growth and adherent Ni-rich outer oxide scale was found on top of the alumina scale throughout the oxidation cycles. The FEA analysis revealed that ODS alloys could be potential high temperature turbine coating materials if micro-channel cooling system is implemented.

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Degradation of thermal barrier coatings on an Integrated Gasification Combined Cycle (IGCC) simulated film-cooled turbine vane pressure surface due to particulate fly ash deposition

Luo¹

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Coal synthesis gas (syngas) can introduce contaminants into the flow of an Integrated Gasification Combined Cycle (IGCC) industrial gas turbine which can form molten deposits onto components of the first stage of a turbine. Research is being conducted at West Virginia University (WVU) to study the effects of particulate deposition on thermal barrier coatings (TBC) employed on the airfoils of an IGCC turbine hot section. WVU had been working with U.S. Department of Energy, National Energy Technology Laboratory (NETL) to simulate deposition on the pressure side of an IGCC turbine first stage vane to study the effects on film cooling. To simulate the particulate deposition, TBC coated, angled film-cooled test articles were subjected to accelerated deposition injected into the flow of a combustor facility with a pressure of approximately 4 atm and a gas temperature of 1560 K. The particle characteristics between engine conditions and laboratory are matched using the Stokes number and particulate loading [1]. To investigate the degradation on the TBC from the particulate deposition, non-destructive evaluations were performed using a load-based multiple-partial unloading micro-indentation technique and were followed by scanning electron microscopy (SEM) evaluation and energy dispersive X-ray spectroscopy (EDS) examinations. The micro-indentation technique used in the study was developed by Kang et al. [2] and can quantitatively evaluate the mechanical properties of materials. The indentation results found that the Young's Modulus of the ceramic top coat is higher in areas with deposition formation due to the penetration of the fly ash. The increase in the modulus of elasticity has been shown to result in a reduction of strain tolerance of the 7% yttria-stabilized zirconia (7YSZ) TBC coatings [3]. I would like to extend my gratitude to Dr. Bruce S. Kang and his Ph.D. student Dumbi A. Otunyo for providing the multiple partial unloading indentation system. Without guidance and use of the system, I would not have been able to perform a quantitative strain tolerance analysis. I've had the pleasure of having Dr. Kang as a supportive figure in my life since I was a young lad at Christian & Missionary Alliance (C&MA) Church.

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Progression in Non-Destructive Spallation Prediction and Elevated Temperature Mechanical Property Evaluation of Thermal Barrier Coating Systems by Use of a Spherical Micro-Indentation Method

Cited by 4 publications

References 96 publications

Effects of Syngas Particulate Fly Ash Deposition on the Mechanical Properties of Thermal Barrier Coatings on Simulated Film-Cooled Turbine Vane Components

Effects of Syngas Particulate Fly Ash Deposition on the Mechanical Properties of Thermal Barrier Coatings on Simulated Film-Cooled Turbine Vane Components

Mechanical and Microstructure Study of Nickel-Based ODS Alloys Processed by Mechano-Chemical Bonding and Ball Milling

Degradation of thermal barrier coatings on an Integrated Gasification Combined Cycle (IGCC) simulated film-cooled turbine vane pressure surface due to particulate fly ash deposition

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