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Mahade, S., Zhou, D., Curry, N., Markocsan, N., Nylén, P. & Vassen, R. (2019). Tailored microstructures of gadolinium zirconate/YSZ multi-layered thermal barrier coatings produced by suspension plasma spray: Durability and erosion testing. Journal of Materials Processing Technology, 264, 283-294
Open this publication in new window or tab >>Tailored microstructures of gadolinium zirconate/YSZ multi-layered thermal barrier coatings produced by suspension plasma spray: Durability and erosion testing
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2019 (English)In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 264, p. 283-294Article in journal (Refereed) Published
Abstract [en]

This work employed an axial suspension plasma spray (SPS) process to deposit two different gadolinium zirconate (GZ) based triple layered thermal barrier coatings (TBCs). The first was a 'layered' TBC (GZ dense/GZ/YSZ) where the base layer was YSZ, intermediate layer was a relatively porous GZ and the top layer was a relatively dense GZ. The second triple layered TBC was a 'composite' TBC (GZ dense/GZ + YSZ/YSZ) comprising of an YSZ base layer, a GZ + YSZ intermediate layer and a dense GZ top layer. The as sprayed TBCs (layered and composite) were characterized using SEM/EDS and XRD. Two different methods (water intrusion and image analysis) were used to measure the porosity content of the as sprayed TBCs. Fracture toughness measurements were made on the intermediate layers (GZ + YSZ layer of the composite TBC and porous GZ layer of the layered TBC respectively) using micro indentation tests. The GZ + YSZ layer in the composite TBC was shown to have a slightly higher fracture toughness than the relatively porous GZ layer in the layered TBC. Erosion performance of the as sprayed TBCs was evaluated at room temperature where the composite TBC showed higher erosion resistance than the layered TBC. However, in the burner rig test conducted at 1400 °C, the layered TBC showed higher thermal cyclic lifetime than the composite TBC. Failure analysis of the thermally cycled and eroded TBCs was performed using SEM and XRD. © 2018 Elsevier B.V.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Composite materials, Durability, Erosion, Failure (mechanical), Gadolinium, Plasma jets, Plasma spraying, Thermal barrier coatings, X ray diffraction, Yttria stabilized zirconia, Burner rig, Erosion resistance, Fracture toughness measurements, Gadolinium zirconate, Intermediate layers, Micro-indentation tests, Suspension plasma sprays, Thermal barrier coating (TBCs), Fracture toughness
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-13041 (URN)10.1016/j.jmatprotec.2018.09.016 (DOI)000450135400028 ()2-s2.0-85053777782 (Scopus ID)
Funder
Knowledge Foundation, 20140130
Available from: 2018-10-29 Created: 2018-10-29 Last updated: 2018-12-20Bibliographically approved
Mahade, S., Ruelle, C., Curry, N., Holmberg, J., Björklund, S., Markocsan, N. & Nylén, P. (2019). Understanding the effect of material composition and microstructural design on the erosion behavior of plasma sprayed thermal barrier coatings. Applied Surface Science, 488, 170-184
Open this publication in new window or tab >>Understanding the effect of material composition and microstructural design on the erosion behavior of plasma sprayed thermal barrier coatings
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2019 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 488, p. 170-184Article in journal (Refereed) Published
Abstract [en]

In this work, three different TBC compositions comprising of yttria partially stabilized zirconia (8YSZ), yttria fully stabilized zirconia (48YSZ) and gadolinium zirconate (GZ) respectively, were processed by suspension plasma spray (SPS) to obtain columnar microstructured TBCs. Additionally, for comparison, lamellar microstructured, 7YSZ TBC was deposited by air plasma spray (APS) process. SEM analysis was carried out to investigate the microstructure and white light interferometry was used to evaluate the surface morphology of the as-sprayed TBCs. Porosity measurements were made using water intrusion and image analysis methods and it was observed that the SPS-YSZ and APS-YSZ TBCs showed higher porosity content than SPS-GZ and SPS-48YSZ. The as-sprayed TBC variations (APS-YSZ, SPS-YSZ, SPS-GZ, and SPS-48YSZ) were subjected to erosion test. Results indicate that the erosion resistance of APS-YSZ TBC was inferior to the SPS-YSZ, SPS-GZ and SPS-48YSZ TBCs respectively. Among the SPS processed TBCs, SPS-YSZ showed the highest erosion resistance whereas the SPS-48YSZ showed the lowest erosion resistance. SEM analysis of the eroded TBCs (cross section and surface morphology) was performed to gain further insights on their erosion behavior. Based on the erosion results and post erosion SEM analysis, erosion mechanisms for splat like microstructured APS TBC and columnar microstructured SPS TBCs were proposed. The findings from this work provide new insights on the erosion mechanisms of columnar microstructured TBCs and lamellar microstructured TBCs deposited by plasma spray. © 2019 Elsevier B.V.

Keywords
Erosion; Microstructure; Morphology; Plasma jets; Porosity; Sprayed coatings; Surface morphology; Thermal barrier coatings; Yttria stabilized zirconia; Yttrium oxide; Zirconia, Atmospheric plasma spray; Gadolinium zirconate; Stabilized zirconia; Suspension plasma sprays; Yttria partially stabilized zirconia, Plasma spraying
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-13987 (URN)10.1016/j.apsusc.2019.05.245 (DOI):000472476200020 ()2-s2.0-85066427612 (Scopus ID)
Funder
Knowledge Foundation, 20140130
Available from: 2019-06-20 Created: 2019-06-20 Last updated: 2019-10-16Bibliographically approved
Mahade, S., Curry, N., Björklund, S., Markocsan, N., Nylén, P. & Vaßen, R. (2017). Erosion Performance of Gadolinium Zirconate-Based Thermal Barrier Coatings Processed by Suspension Plasma Spray. Journal of thermal spray technology (Print), 26(1-2), 108-115
Open this publication in new window or tab >>Erosion Performance of Gadolinium Zirconate-Based Thermal Barrier Coatings Processed by Suspension Plasma Spray
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2017 (English)In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 26, no 1-2, p. 108-115Article in journal (Refereed) Published
Abstract [en]

7-8 wt.% Yttria-stabilized zirconia (YSZ) is the standard thermal barrier coating (TBC) material used by the gas turbines industry due to its excellent thermal and thermo-mechanical properties up to 1200 °C. The need for improvement in gas turbine efficiency has led to an increase in the turbine inlet gas temperature. However, above 1200 °C, YSZ has issues such as poor sintering resistance, poor phase stability and susceptibility to calcium magnesium alumino silicates (CMAS) degradation. Gadolinium zirconate (GZ) is considered as one of the promising top coat candidates for TBC applications at high temperatures (>1200 °C) due to its low thermal conductivity, good sintering resistance and CMAS attack resistance. Single-layer 8YSZ, double-layer GZ/YSZ and triple-layer GZdense/GZ/YSZ TBCs were deposited by suspension plasma spray (SPS) process. Microstructural analysis was carried out by scanning electron microscopy (SEM). A columnar microstructure was observed in the single-, double- and triple-layer TBCs. Phase analysis of the as-sprayed TBCs was carried out using XRD (x-ray diffraction) where a tetragonal prime phase of zirconia in the single-layer YSZ TBC and a cubic defect fluorite phase of GZ in the double and triple-layer TBCs was observed. Porosity measurements of the as-sprayed TBCs were made by water intrusion method and image analysis method. The as-sprayed GZ-based multi-layered TBCs were subjected to erosion test at room temperature, and their erosion resistance was compared with single-layer 8YSZ. It was shown that the erosion resistance of 8YSZ single-layer TBC was higher than GZ-based multi-layered TBCs. Among the multi-layered TBCs, triple-layer TBC was slightly better than double layer in terms of erosion resistance. The eroded TBCs were cold-mounted and analyzed by SEM.

Keywords
columnar microstructureerosion, test gadolinium, zirconatemulti-layered thermal barrier, coating, suspension plasma spray, yttria-stabilized zirconia
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-10498 (URN)10.1007/s11666-016-0479-4 (DOI)000392060300011 ()2-s2.0-85001975445 (Scopus ID)
Funder
Knowledge Foundation, 20140130
Note

This article is an invited paper selected from presentations at the 2016 International Thermal Spray Conference, held May 10-12, 2016, in Shanghai, P. R. China, and has been expanded from the original presentation.

Available from: 2017-01-09 Created: 2017-01-09 Last updated: 2019-01-29Bibliographically approved
Mahade, S., Curry, N., Björklund, S., Markocsan, N., Nylén, P. & Vassen, R. (2017). Functional performance of Gd2Zr2O7/YSZ multi-layered thermal barrier coatings deposited by suspension plasma spray. Surface & Coatings Technology, 318, 208-216
Open this publication in new window or tab >>Functional performance of Gd2Zr2O7/YSZ multi-layered thermal barrier coatings deposited by suspension plasma spray
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2017 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 318, p. 208-216Article in journal (Refereed) Published
Abstract [en]

7-8 wt% yttria stabilized zirconia (YSZ) is the standard ceramic top coat material used in gasturbines to insulate the underlying metallic substrate. However, at higher temperatures(>1200 °C), phase stability and sintering becomes an issue for YSZ. At these temperatures,YSZ is also susceptible to CMAS (calcium magnesium alumino silicates) infiltration. New ceramic materials such as pyrochlores have thus been proposed due to their excellent properties such as lower thermal conductivity and better CMAS attack resistance compared to YSZ. However, pyrochlores have inferior thermo mechanical properties compared to YSZ.Therefore, double-layered TBCs with YSZ as the intermediate layer and pyrochlore as the top ceramic layer have been proposed. In this study, double layer TBC comprising gadoliniumzirconate (GZ)/YSZ and triple layer TBC (GZdense/GZ/YSZ) comprising relatively denser GZtop layer on GZ/YSZ were deposited by suspension plasma spray. Also, single layer 8YSZ TBC was suspension plasma sprayed to compare its functional performance with the multilayered TBCs. Cross sections and top surface morphology of as sprayed TBCs were analyzed by scanning electron microscopy (SEM). XRD analysis was done to identify phases formed in the top surface of as sprayed TBCs. Porosity measurements were made using water intrusionand image analysis methods. Thermal diffusivity of the as sprayed TBCs was measured using laser flash analysis and thermal conductivity of the TBCs was calculated. The multi-layered GZ/YSZ TBCs were shown to have lower thermal conductivity than the single layer YSZ. Theas sprayed TBCs were also subjected to thermal cyclic testing at 1300 ºC. The double and triple layer TBCs had a longer thermal cyclic life compared to YSZ. The failed samples were cold mounted and analyzed by SEM.

Keywords
Columnar microstructure, Gadolinium zirconate, Multi-layered thermal barrier coating, Suspension plasma spray, Thermal conductivity, Thermal cyclic test, Yttria stabilized zirconia
National Category
Production Engineering, Human Work Science and Ergonomics
Research subject
Production Technology; ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-9855 (URN)10.1016/j.surfcoat.2016.12.062 (DOI)000402356100024 ()2-s2.0-85009266708 (Scopus ID)
Funder
Knowledge Foundation, 20140130
Note

Ingår i licuppsats

Available from: 2016-09-05 Created: 2016-09-05 Last updated: 2019-01-30Bibliographically approved
Jonnalagadda, K. P., Mahade, S., Curry, N., Li, X.-H., Markocsan, N., Nylen, P., . . . Peng, R. L. (2017). Hot Corrosion Mechanism in Multi-Layer Suspension Plasma Sprayed Gd2Zr2O7 /YSZ Thermal Barrier Coatings in the Presence of V2O5 + Na2SO4. Journal of thermal spray technology (Print), 26(1-2), 140-149
Open this publication in new window or tab >>Hot Corrosion Mechanism in Multi-Layer Suspension Plasma Sprayed Gd2Zr2O7 /YSZ Thermal Barrier Coatings in the Presence of V2O5 + Na2SO4
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2017 (English)In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 26, no 1-2, p. 140-149Article in journal (Refereed) Published
Abstract [en]

This study investigates the corrosion resistance of two-layer Gd2Zr2O7/YSZ, three-layer dense Gd2Zr2O7/ Gd2Zr2O7/YSZ, and a reference single-layer YSZ coating with a similar overall top coat thickness of 300-320 µm. All the coatings were manufactured by suspension plasma spraying resulting in a columnar structure except for the dense layer. Corrosion tests were conducted at 900 °C for 8 h using V2O5 and Na2SO4 as corrosive salts at a concentration of approximately 4 mg/cm2. SEM investigations after the corrosion tests show that Gd2Zr2O7-based coatings exhibited lower reactivity with the corrosive salts and the formation of gadolinium vanadate (GdVO4), accompanied by the phase transformation of zirconia was observed. It is believed that the GdVO4 formation between the columns reduced the strain tolerance of the coating and also due to the fact that Gd2Zr2O7 has a lower fracture toughness value made it more susceptible to corrosion-induced damage. Furthermore, the presence of a relatively dense layer of Gd2Zr2O7 on the top did not improve in reducing the corrosion-induced damage. For the reference YSZ coating, the observed corrosion-induced damage was lower probably due to combination of more limited salt penetration, the SPS microstructure and superior fracture toughness of YSZ.

Keywords
gadolinium zirconatehot corrosionmulti-layer thermal barrier coatingssuspension plasma sprayingvanadium pentoxide + sodium sulfate
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-10490 (URN)10.1007/s11666-016-0486-5 (DOI)000392060300014 ()2-s2.0-85001686856 (Scopus ID)
Funder
VINNOVA
Available from: 2017-01-04 Created: 2017-01-04 Last updated: 2019-02-28Bibliographically approved
Ganvir, A., Curry, N., Markocsan, N. & Govindarajan, S. (2016). Characterization of Thermal Barrier Coatings Produced by Various Thermal Spray Techniques Using Solid Powder, Suspension, and Solution Precursor Feedstock Material. International Journal of Applied CeramicTechnology, 13(2), 324-332
Open this publication in new window or tab >>Characterization of Thermal Barrier Coatings Produced by Various Thermal Spray Techniques Using Solid Powder, Suspension, and Solution Precursor Feedstock Material
2016 (English)In: International Journal of Applied CeramicTechnology, ISSN 1546-542X, Vol. 13, no 2, p. 324-332Article in journal (Refereed) Published
Abstract [en]

Use of a liquid feedstock in thermal spraying (an alternative to the conventional solid powder feedstock) is receiving an increasing level of interest due to its capability to produce the advanced submicrometer/nanostructured coatings. Suspension plasma spraying (SPS) and solution precursor plasma spraying (SPPS) are those advanced thermal spraying techniques which help to feed this liquid feedstock. These techniques have shown to produce better performance thermal barrier coatings (TBCs) than conventional thermal spraying. In this work, a comparative study was performed between SPS- and SPPS-sprayed TBCs which then were also compared with the conventional atmospheric plasma-sprayed (APS) TBCs. Experimental characterization included SEM, porosity analysis using weight difference by water infiltration, thermal conductivity measurements using laser flash analysis, and lifetime assessment using thermo-cyclic fatigue test. It was concluded that SPS coatings can produce a microstructure with columnar type features (intermediary between the columnar and vertically cracked microstructure), whereas SPPS can produce vertically cracked microstructure. It was also shown that SPS coatings with particle size in suspension (D50) <3 μm were highly porous with lower thermal conductivity than SPPS and APS coatings. Furthermore, SPS coatings have also shown a relatively better thermal cyclic fatigue lifetime than SPPS.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2016
Keywords
Thermal spraying, coating, spray techniques
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology; ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-8636 (URN)10.1111/ijac.12472 (DOI)000372037300017 ()2-s2.0-84960358653 (Scopus ID)
Note

Article first published online:11 September 2015

Available from: 2015-11-11 Created: 2015-11-11 Last updated: 2019-05-21Bibliographically approved
Kovářík, O., Haušild, P., Čapek, J., Medřický, J., Siegl, J., Mušálek, R., . . . Björklund, S. (2016). Damping measurement during resonance fatigue test and its application for crack detection in TBC samples. Paper presented at 10th Fatigue Damage of Structural Materials Conference. International Journal of Fatigue, 82(Part 2), 300-309
Open this publication in new window or tab >>Damping measurement during resonance fatigue test and its application for crack detection in TBC samples
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2016 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 82, no Part 2, p. 300-309Article in journal (Refereed) Published
Abstract [en]

Abstract The use of specimen loss factor as fatigue damage indicator of Hastelloy-X substrates with different surface treatments was investigated together with other fatigue damage indicators, namely resonance frequency and crack mouth length. The tested surface treatments included grit-blasting and plasma spraying of NiCoCrAlY bond coat and yttria stabilized zirconia (YSZ) top coat. The loss factors of fatigue test specimens were measured repeatedly during the resonance bending fatigue test using the conventional free decay method. The analysis of the damping spectra, i.e. the model describing the relation of loss factor to maximum macroscopic specimen strain εyy was drafted. The model is based on the combination of defect models developed by Göken and Riehemann [1] and classical dislocation model of Granato and LÌcke [2]. It appears, that the damping spectra can be well approximated as a combination of two defect peaks (C1 and C2) and one dislocation peak (D1). The low strain defect peak (peak C1) is sensitive to the presence of fatigue cracks. The second defect peak (peak C2) can be attributed to the remaining substrate and coating defects such as embedded grit particles, coating porosity, surface roughness and sliding in the sample clamping area. The fatigue damage detection using the C1 peak magnitude was performed and its results were related to the crack length obtained by digital image correlation (DIC) method. In the crack initiation stage I., the C1 peak height shows different behavior than the resonance frequency and therefore provides new information. The underlying processes causing C1 peak changes need to be found yet, however. In the crack growth stage II., both resonance frequency and peak height C1 correlate with the measured fatigue crack size.

Keywords
Hastelloy-X, Fatigue, Resonance, Damping, Crack detection, Nondestructive testing, DIC
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-7908 (URN)10.1016/j.ijfatigue.2015.07.026 (DOI)
Conference
10th Fatigue Damage of Structural Materials Conference
Available from: 2015-08-14 Created: 2015-08-14 Last updated: 2018-11-13Bibliographically approved
Mahade, S., Björklund, S., Markocsan, N., Curry, N. & Vassen, R. (2016). Erosion Behavior of Gadolinium Zirconate/YSZ Multi-Layered Thermal Barrier Coatings Deposited by Suspension Plasma Spray. In: Proceedings of the International Thermal Spray Conference: . Paper presented at International Thermal Spray Conference, May 10-12, 2016, Shanghai, DVS Media (pp. 343-347).
Open this publication in new window or tab >>Erosion Behavior of Gadolinium Zirconate/YSZ Multi-Layered Thermal Barrier Coatings Deposited by Suspension Plasma Spray
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2016 (English)In: Proceedings of the International Thermal Spray Conference, 2016, p. 343-347Conference paper, Published paper (Refereed)
Abstract [en]

Yttria stabilized zirconia (8YSZ) is the standard ceramic material for thermal barrier coating (TBC)applications. However, above 1200º C, it has limitations such as poor sintering resistance & susceptibility to CMAS(Calcium Magnesium Alumino Silicates) degradation. Gadolinium zirconate (GZ) is considered as one of the promising top coat candidates for TBC applications at high temperature (>1200 ºC) due to its lower thermal conductivity, good sintering resistance and CMAS infiltration resistance. Single layer 8YSZ, double layer GZ/YSZand triple layer GZdense/GZ/YSZ TBCs were deposited by suspension plasma spray (SPS). Microstructuralanalysis was carried out by SEM (scanning electron microscopy). Phase analysis of as sprayed TBCs was carriedout using XRD (X ray diffraction). The as sprayed multi-layered TBCs were subjected to erosion test at room temperature and their erosion resistance was compared with single layer 8YSZ. It was observed that the erosion resistance of 8YSZ TBC was higher than GZ/YSZ multi-layered TBCs at room temperature. Among the multilayered TBCs, triple layer TBC was slightly better than double layer in terms of erosion resistance.

Keywords
Thermal barrier coating
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-9856 (URN)2-s2.0-85026871726 (Scopus ID)
Conference
International Thermal Spray Conference, May 10-12, 2016, Shanghai, DVS Media
Available from: 2016-09-05 Created: 2016-09-05 Last updated: 2019-02-07Bibliographically approved
Mahade, S., Curry, N., Björklund, S., Markocsan, N. & Nylén, P. (2016). Failure analysis of Gd2Zr2O7/YSZ multi-layered thermal barrier coatings subjected to thermal cyclic fatigue. Journal of Alloys and Compounds, 689, 1011-1019
Open this publication in new window or tab >>Failure analysis of Gd2Zr2O7/YSZ multi-layered thermal barrier coatings subjected to thermal cyclic fatigue
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2016 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 689, p. 1011-1019Article in journal (Refereed) Published
Abstract [en]

8 wt.% yttria stabilized zirconia (8YSZ) is the standard ceramic top coat material used in thermal barrier coatings (TBCs) due to its excellent thermo-physical and thermo-mechanical properties. However, above 1200 °C, YSZ has issues such as susceptibility to CMAS (Calcium Magnesium Alumino Silicates) attack and enhanced sintering which could lead to catastrophic failure of the TBC. Pyrochlores of rare earth zirconate composition such as gadolinium zirconate have shown to be resistant to CMAS attack and at the same time possess several other attractive properties. However, poor thermal cycling life of single layer gadolinium zirconate (GZ) TBC compared to single layer YSZ has been reported. Therefore, a double layered GZ/YSZ TBC with YSZ as the intermediate coating and GZ as the top coat and a single layer 8YSZ were deposited by the axial suspension plasma spray process. Additionally, a triple layer TBC (GZdense/GZ/YSZ) comprising of denser GZ coating on top of GZ/YSZ TBC was deposited. SEM analysis revealed a columnar microstructure in the single, double and triple layer TBCs. XRD analysis confirmed the presence of tetragonal prime and defect fluorite phases in the top surface of YSZ and GZ based as sprayed TBCs respectively. The single layer YSZ and GZ/YSZ multi-layered TBCs were subjected to thermal cyclic fatigue (TCF) testing at 1100 °C and 1200 °C. The triple layer TBC showed a higher thermal cyclic life at both the temperatures compared to the single and double layer TBCs. The failed TBCs at 1100 °C were analyzed by SEM/EDS and image analysis. It was found that the failure modes in single layer YSZ and GZ based TBCs were different.

Keywords
Gadolinium zirconate, yttria stabilized zirconia, axial suspension plasma spray, multi-layered thermal barrier coating, columnar microstructure, thermal cyclic fatigue
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-9811 (URN)10.1016/j.jallcom.2016.07.333 (DOI)000384427200129 ()2-s2.0-84982239051 (Scopus ID)
Funder
Knowledge Foundation, 20140130
Available from: 2016-08-26 Created: 2016-08-26 Last updated: 2019-03-15Bibliographically approved
Musalek, R., Kovarik, O., Tomek, L., Medricky, J., Pala, Z., Hausild, P., . . . Björklund, S. (2016). Fatigue Performance of TBCs on Hastelloy X Substrate During Cyclic Bending. Journal of thermal spray technology (Print), 25(1-2), 231-243
Open this publication in new window or tab >>Fatigue Performance of TBCs on Hastelloy X Substrate During Cyclic Bending
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2016 (English)In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 25, no 1-2, p. 231-243Article in journal (Refereed) Published
Abstract [en]

Our previous experiments with low-cost steel substrates confirmed that individual steps of conventional thermal barrier coating (TBC) deposition may influence fatigue properties of the coated samples differently. In the presented study, testing was carried out for TBC samples deposited on industrially more relevant Hastelloy X substrates. Samples were tested after each step of the TBC deposition process: as-received (non-coated), grit-blasted, bond-coated (NiCoCrAlY), and bond-coated + top-coated yttria-stabilized zirconia (YSZ). Conventional atmospheric plasma spraying (APS) was used for deposition of bond coat and top coat. In addition, for one half of the samples, dual-layer bond coat was prepared by combination of high-velocity air-fuel (HVAF) and APS processes. Samples were tested in the as-sprayed condition and after 100 hours annealing at 980 °C, which simulated application-relevant in-service conditions. Obtained results showed that each stage of the TBC manufacturing process as well as the simulated in-service heat exposure may significantly influence the fatigue properties of the TBC coated part. HVAF grit-blasting substantially increased the fatigue performance of the uncoated substrates. This beneficial effect was suppressed by deposition of APS bond coat but not by deposition of dual-layer HVAF + APS bond coat. All heat-treated samples showed again enhanced fatigue performance. © 2015 ASM International

Keywords
Air, Coatings, Deposition, Fatigue of materials, Plasma jets, Plasma spraying, Substrates, Thermal barrier coatings, Yttrium alloys, Zirconia, Atmospheric plasma spray, Failure mechanism, HVAF, NiCoCrAlY, Thermal barrier coating (TBCs), Yttria-stabilized zirconias (YSZ), Yttria stabilized zirconia
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-8710 (URN)10.1007/s11666-015-0321-4 (DOI)000374268000024 ()2-s2.0-84953639179 (Scopus ID)
Note

Funders: Czech Science Foundation,  14-36566G

Available from: 2015-12-01 Created: 2015-11-24 Last updated: 2019-02-07Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-0209-1332

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