| 1. |
- Adli, Erik, et al.
(author)
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Progress Of The Ess Proton Beam Imaging Systems
- 2022
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In: LINAC2022. - : ACoW Publishing. ; , s. 395-398
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Conference paper (peer-reviewed)abstract
- The ESS Target Proton Beam Imaging Systems has the objective to image the 5 MW ESS proton beam as it entersthe spallation target. The imaging systems has to operate in a harsh radiation environment, leading to a number of challenges : development of radiation hard photon sources, long and aperture-restricted optical paths and fast electronics required to provide rapid information in case of beam anomalies. This paper outlines how main challenges of the imaging systems have been addressed, and the status of deployment as ESS gets closer to beam.
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| 2. |
- Baiamonte, Lidia, et al.
(author)
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Carbide-laden coatings deposited using a hand-held high-velocity air-fuel (HVAF) spray gun
- 2021
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In: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 406
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Journal article (peer-reviewed)abstract
- Driven by sustainability and cost considerations, there is growing interest in power generation utilizing renewable sources, especially biomass and waste. While premature degradation of power plant components due to corrosion is well-known, erosion can be a dominant damage mechanism in plants that use “pure” biomass with less corrosive elements like Cl, K, etc. Circulating fluidized bed (CFB) parts are prone to erosion-driven damage and demand periodic re-protection or replacement. In response to the above, this preliminary study evaluates a selection of complex carbide-based coatings to enhance protection against erosion to prolong service life of boiler components. Recognizing on-site coating requirements of real boiler applications, a specific focus is on evaluating performance of a hand-held high-velocity air-fuel (HVAF) spray gun and compare it with the current state-of-the-art high-velocity oxy-fuel (HVOF) deposition. Coatings developed by the above routes have been characterized with microstructural analyses, and their performance evaluated and ranked in an air-jet erosion rig at various impact angles.
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| 3. |
- Bellippady, Madhura, et al.
(author)
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Characteristics and performance of suspension plasma sprayed thermal barrier coatings on additively manufactured superalloy substrates
- 2023
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In: Surface and Coatings Technology. - : Elsevier. - 0257-8972. ; 472
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Journal article (peer-reviewed)abstract
- The complex-shaped hot-section parts of new-generation turbine engines demand unique design solutions. Additive Manufacturing (AM) is an emergent production method that can produce metallic parts with complex geometries and minimal material wastage. In this work, the characteristics and performance behavior of Thermal Barrier Coatings (TBCs) deposited on forged and AM-built HAYNES®282® superalloy substrates were studied and compared. The bond coats were produced by High-Velocity Air-Fuel (HVAF) spraying using NiCoCrAlY powder feedstock and TBC top-coats by Suspension Plasma Spraying (SPS) using water- and ethanol-based suspensions of Yttria-Stabilized Zirconia (YSZ). The microstructural features, adhesion, Thermal Cycling Fatigue (TCF) lifetime, and thermal shock lifetimes of the TBCs were comprehensively investigated. The results showed that the deposition of bond coats reduced the roughness and asperities of the AM-built substrates. Depending on the type of suspension used and the spray parameters employed, the TBCs exhibited vertically cracked and columnar microstructures. However, no significant differences in TCF and thermal shock lifetimes of TBCs on AM and forged substrates were observed. It is demonstrated that TBC systems can be produced on AM-built metallic substrates, and the resulting TBCs can have similar microstructures and properties as TBCs deposited on conventional substrates.
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| 4. |
- Bellippady, Madhura, et al.
(author)
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Performance of Atmospheric Plasma-Sprayed Thermal Barrier Coatings on Additively Manufactured Super Alloy Substrates
- 2024
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In: Coatings. - : MDPI. - 2079-6412. ; 14:5
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Journal article (peer-reviewed)abstract
- This work represents a preliminary study of atmospheric plasma-sprayed (APS) YttriaStabilized Zirconia (YSZ)-based thermal barrier coatings (TBCs) deposited on forged and additivemanufactured (AM) HAYNES®282® (H282) superalloy substrates. The effect of different feedstockmorphologies and spray gun designs with radial and axial injection on APS-deposited YSZ layercharacteristics such as microstructure, porosity content, roughness, etc., has been investigated. Theperformance of TBCs in terms of thermal cycling fatigue (TCF) lifetime and erosion behaviour werealso comprehensively investigated. In view of the high surface roughness of as-built AM surfacescompared to forged substrates, two different types of NiCoCrAlY bond coats were examined: oneinvolved high-velocity air fuel (HVAF) spraying of a finer powder, and the other involved APSdeposition of a coarser feedstock. Despite the process and feedstock differences, the above two routesyielded comparable bond coat surface roughness on both types of substrates. Variation in porositylevel in the APS topcoat was observed when deposited using different YSZ feedstock powdersemploying axial or radial injection. However, the resultant TBCs on AM-derived substrates wereobserved to possess similar microstructures and functional properties as TBCs deposited on reference(forged) substrates for any given YSZ deposition process and feedstock.
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| 5. |
- Bellippady, Madhura, et al.
(author)
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Process Parameter Impact on Axial Plasma Sprayed Ytterbium Disilicate Coatings for Environment Barrier Coating Applications
- 2024
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In: Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning. - : IOS Press. - 9781643685106 - 9781643685113 ; , s. 101-110
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Book chapter (peer-reviewed)abstract
- In future generation aviation, light weight, and thermally stable SiC/SiC ceramic matrix composites (CMCs) are considered the most promising structural materials to replace traditionally used Ni-based superalloys. However, in the presence of steam (a common combustion reaction product) and corrosive species (from ingestion of debris along with the intake air during take-off and landing), accelerated degradation of CMCs compromising its structural integrity is inevitable. Environmental Barrier Coatings (EBCs) are protective ceramic coatings consisting of rare earth (RE) silicates as a topcoat with silicon as a bond coat, and are widely used on CMCs, to impede their surface recession.Thermal spray techniques are commonly employed to deposit EBCs, with highly crystalline, dense, and crack free coatings being desired for robust performance. In general, the high particle velocity and efficient energy transfer in axial feeding systems can result in coatings with higher density, reduced oxide content, and improved mechanical properties. In the present study, axial plasma sprayed ytterbium disilicate (YbDS) coatings deposited on silicon carbide (SiC) substrates using varying plasma spray parameters have been comprehensively characterized. Microstructure, porosity, and hardness have been studied for YbDS coatings deposited by varying nozzle diameter, carrier gas flow rate and stand of distance (SOD) during plasma spraying. Erosion and thermal cyclic fatigue performance of these coatings has also been investigated.
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| 6. |
- Björklund, Stefan, 1969-, et al.
(author)
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Function-dependent coating architectures by hybrid powder-suspension plasma spraying : Injector design, processing and concept validation
- 2018
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In: Materials & design. - : Elsevier BV. - 0264-1275 .- 1873-4197. ; 142, s. 56-65
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Journal article (peer-reviewed)abstract
- The attractive properties achieved by Suspension Plasma Spraying (SPS), combined with the availability of high throughput capable plasma spray systems that permit axial feeding, provide encouragement to explore use of suspensions for next generation functional applications. This paper deals with realization of coatings with various pre-determined function-dependent architectures by employing a hybrid powder-suspension feedstock. Some illustrative application-relevant coating architecture designs are discussed, along with the specific benefits that can accrue by deploying a multi-scale powder-suspension feedstock combination. An elegant feedstock delivery arrangement to enable either simultaneous or sequential feeding of powders and suspensions to enable convenient processing of coatings with desired architectures is presented. As proof-of-concept, deposition of layered, composite and functionally graded coatings using the above system is also demonstrated using appropriate case studies
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| 7. |
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| 8. |
- Choquet, Isabelle, 1965-, et al.
(author)
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Clogging and lump formation during atmospheric plasma spraying with powder injection downstream the plasma gun
- 2007
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In: Journal of thermal spray technology (Print). - : Springer Science and Business Media LLC. - 1059-9630 .- 1544-1016. ; 16:4, s. 512-523
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Journal article (peer-reviewed)abstract
- This study aimed to numerically and experimentally investigate lump formation during atmospheric plasma spraying with powder injection downstream the plasma gun exit. A first set of investigations was focused on the location and orientation of the powder port injector. It turned out impossible to keep the coating quality while avoiding lumps by simply moving the powder injector. A new geometry of the powder port ring holder was designed and optimized to prevent nozzle clogging, and lump formation using a gas screen. This solution was successfully tested for applications with Ni-5wt.%Al and ZrO2-7wt.%Y2O3 powders used in production. The possible secondary effect of plasma jet shrouding by the gas screen, and its consequence on powder particles prior to impact was also studied.
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| 9. |
- Choquet, Isabelle, 1965-, et al.
(author)
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New powder port holder geometry to avoid lump formation in APS
- 2005
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In: 17th international symposium on plasma chemistry (ISPC 17). ; , s. OP7. 1-6
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Conference paper (other academic/artistic)abstract
- A new geometry of the powder port ring holder used in atmospheric plasma spraying has recently been designed to avoid lump formation, and successfully tested for a set of process parameters associated with Ni-5Al powder used in production to form bond coat [1]. But with ZrO 2 powder used to made top coat, improvements were not enough satisfactory. Here, we investigate numerically the cause of the remaining defects, and further improve the ring geometry to prevent lump from forming in any part of the coating.
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| 10. |
- Curry, Nicholas, et al.
(author)
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Performance Testing of Suspension Plasma Sprayed Thermal Barrier Coatings Produced with Varied Suspension Parameters
- 2015
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In: Coatings. - : MDPI AG. - 2079-6412. ; 5:3, s. 338-356
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Journal article (peer-reviewed)abstract
- Suspension plasma spraying has become an emerging technology for the production of thermal barrier coatings for the gas turbine industry. Presently, though commercial systems for coating production are available, coatings remain in the development stage. Suitable suspension parameters for coating production remain an outstanding question and the influence of suspension properties on the final coatings is not well known. For this study, a number of suspensions were produced with varied solid loadings, powder size distributions and solvents. Suspensions were sprayed onto superalloy substrates coated with high velocity air fuel (HVAF) -sprayed bond coats. Plasma spray parameters were selected to generate columnar structures based on previous experiments and were maintained at constant to discover the influence of the suspension behavior on coating microstructures. Testing of the produced thermal barrier coating (TBC) systems has included thermal cyclic fatigue testing and thermal conductivity analysis. Pore size distribution has been characterized by mercury infiltration porosimetry. Results show a strong influence of suspension viscosity and surface tension on the microstructure of the produced coatings.
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