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11. Process qualification, additive manufacturing, and postprocessing of a hydrogen peroxide/kerosene 6 kN aerospike breadboard engine.

Author

Selbmann, Alex, Gruber, Samira, Propst, Martin, Dorau, Tim, Drexler, Robert, Toma, Filofteia-Laura, Mueller, Michael, Stepien, Lukas, Lopez, Elena, Bach, Christian, Brueckner, Frank, and Leyens, Christoph

Subjects
THERMAL barrier coatings, HYDROGEN peroxide, KEROSENE, MECHANICAL heat treatment, LASER welding, MANUFACTURING processes
Abstract

This contribution addresses the complete process chain of an annular aerospike breadboard engine fabricated by laser powder bed fusion using the nickel-based superalloy Inconel® 718. In order to qualify the material and process for this high-temperature application, an extensive material characterization campaign including density and roughness measurements, as well as tensile tests at room temperature, 700, and 900 °C, was conducted. In addition, various geometric features such as triangles, ellipses, and circular shapes were generated to determine the maximum unsupported overhang angle and geometrical accuracy. The results were taken into account in the design maturation of the manifold and the cooling channels of the aerospike breadboard engine. Postprocessing included heat treatment to increase mechanical properties, milling, turning, and eroding of interfaces to fulfill the geometrical tolerances, thermal barrier coating of thermally stressed surfaces for better protection of thermal loads, and laser welding of spike and shroud for the final assembly as well as quality assurance. This contribution goes beyond small density cubes and tensile samples and offers details on the iterations necessary for the successful printing of large complex shaped functional parts. The scientific question is how to verify the additive manufacturing process through tensile testing, simulation, and design iterations for complex geometries and reduce the number of failed prints. [ABSTRACT FROM AUTHOR]

Published
2024
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16. The 2016 Thermal Spray Roadmap

Author

Vardelle, Armelle, Moreau, Christian, Akedo, Jun, Ashrafizadeh, Hossein, Berndt, Christopher C., Berghaus, Jörg Oberste, Boulos, Maher, Brogan, Jeffrey, Bourtsalas, Athanasios C., Dolatabadi, Ali, Dorfman, Mitchell, Eden, Timothy J., Fauchais, Pierre, Fisher, Gary, Gaertner, Frank, Gindrat, Malko, Henne, Rudolf, Hyland, Margaret, Irissou, Eric, Jordan, Eric H., Khor, Khiam Aik, Killinger, Andreas, Lau, Yuk-Chiu, Li, Chang-Jiu, Li, Li, Longtin, Jon, Markocsan, Nicolaie, Masset, Patrick J., Matejicek, Jiri, Mauer, Georg, McDonald, André, Mostaghimi, Javad, Sampath, Sanjay, Schiller, Günter, Shinoda, Kentaro, Smith, Mark F., Syed, Asif Ansar, Themelis, Nickolas J., Toma, Filofteia-Laura, Trelles, Juan Pablo, Vassen, Robert, and Vuoristo, Petri

Published
2016
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18. Development of Suspension Feedstocks for Thermally Sprayed Zn2TiO4 Coatings.

Author

Meyer, Anja, Toma, Filofteia-Laura, Kunze, Oliver, Böhme, Andreas, Matthey, Björn, Potthoff, Annegret, Kaiser, Arno, Gestrich, Tim, and Leyens, Christoph

Subjects
*SURFACE coatings, *DIFFERENTIAL thermal analysis, *PROTECTIVE coatings, *FEEDSTOCK, *METAL spraying, *PHOTOCATALYSTS, *RAW materials
Abstract

By adjusting the thermal spraying suspension technology, coatings with excellent microstructure, surface morphology, and phase composition can be obtained to meet the application needs in mechanical, electrical or friction fields. The use of suspensions as feedstock material allows a high degree of flexibility with regard to the chemical composition of the sprayed coatings. Moreover, suspension thermal spraying (STS) is a promising technique for the production of coatings, the use of which was previously limited by expensive starting materials. A mixture of less expensive starting materials in the suspension and an "in situ" reaction to the desired product during the spraying process make this possible. Zn2TiO4 coatings are one example where the high costs of blended oxide powders as feedstock material hinder the market introduction, whereas their outstanding electrical properties and photocatalytic activity are of great interest for various industrial applications. In this work, single oxides ZnO and TiO2, Zn acetate salt as ZnO precursor, as well as a Zn2TiO4 powder were used to develop tailored aqueous suspension feedstocks suitable for thermal spraying. To follow the formation of the compositions in the system ZnO-TiO2, differential thermal analysis (DTA) measurements were performed. Preparation routes of stable suspensions and suspension-solution mixtures with low sedimentation rates, low viscosities and good flowabilities are discussed. Microstructures and phase compositions of sprayed coatings are shown, and the "in situ" formation of Zn2TiO4 phase during Suspension High Velocity Oxygen Fuel Spraying (S-HVOF) is demonstrated. This work shows the high potential of suspension feedstocks from single oxide raw materials to obtain Zn2TiO4 sprayed coatings. [ABSTRACT FROM AUTHOR]

Published
2023
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22. Erratum to: The 2016 Thermal Spray Roadmap

Author

Vardelle, Armelle, Moreau, Christian, Akedo, Jun, Ashrafizadeh, Hossein, Berndt, Christopher C., Berghaus, Jörg Oberste, Boulos, Maher, Brogan, Jeffrey, Bourtsalas, Athanasios C., Dolatabadi, Ali, Dorfman, Mitchell, Eden, Timothy J., Fauchais, Pierre, Fisher, Gary, Gaertner, Frank, Gindrat, Malko, Henne, Rudolf, Hyland, Margaret, Irissou, Eric, Jodoin, Bertrand, Jordan, Eric H., Khor, Khiam Aik, Killinger, Andreas, Lau, Yuk-Chiu, Li, Chang-Jiu, Li, Li, Longtin, Jon, Markocsan, Nicolaie, Masset, Patrick J., Matejicek, Jiri, Mauer, Georg, McDonald, André, Mostaghimi, Javad, Sampath, Sanjay, Schiller, Günter, Shinoda, Kentaro, Smith, Mark F., Syed, Asif Ansar, Themelis, Nickolas J., Toma, Filofteia-Laura, Trelles, Juan Pablo, Vassen, Robert, and Vuoristo, Petri

Published
2017
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25. Wear Behavior Analysis of Al2O3 Coatings Manufactured by APS and HVOF Spraying Processes Using Powder and Suspension Feedstocks

Author

Michalak, Monika, Sokolowski, Pawel, Szala, Miroslaw, Walczak, Mariusz, Latka, Leszek, Toma, Filofteia-Laura, Björklund, Stefan, Michalak, Monika, Sokolowski, Pawel, Szala, Miroslaw, Walczak, Mariusz, Latka, Leszek, Toma, Filofteia-Laura, and Björklund, Stefan

Abstract

Thermally sprayed ceramic coatings are applied for the protection of surfaces that are exposed mainly to wear, high temperatures, and corrosion. In recent years, great interest has been garnered by spray processes with submicrometric and nanometric feedstock materials, due to the refinement of the structure and improved coating properties. This paper compares the microstructure and tribological properties of alumina coatings sprayed using conventional atmospheric plasma spraying (APS), and various methods that use finely grained suspension feedstocks, namely, suspension plasma spraying (SPS) and suspension high-velocity oxy-fuel spraying (S-HVOF). Furthermore, the suspension plasma-sprayed Al2O3 coatings have been deposited with radial (SPS) and axial (A-SPS) feedstock injection. The results showed that all suspension-based coatings demonstrated much better wear resistance than the powder-sprayed ones. S-HVOF and axial suspension plasma spraying (A-SPS) allowed for the deposition of the most dense and homogeneous coatings. Dense-structured coatings with low porosity (4 vol.%) and good cohesion to the metallic substrate, containing a high content of alpha-Al2O3 phase (56 vol.%) and a very low wear rate (0.2 +/- 0.04 mm(3) x 10(-6)/(N center dot m)), were produced with the S-HVOF method. The wear mechanism of ceramic coatings included the adhesive wear mode supported by the fatigue-induced material delamination. Moreover, the presence of wear debris and tribofilm was confirmed. Finally, the coefficient of friction for the coatings was in the range between 0.44 and 0.68, with the highest values being recorded for APS sprayed coatings.

Published
2021
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29. Special issue featuring papers from the international thermal spray conference (ITSC) 2019

Author

McDonald, André, Azarmi, Fardad, Balani, Kantesh, Cizek, Jan, Koivuluoto, Heli, Lau, Yuk-Chiu, Li, Hua, Toma, Filofteia-Laura, and Publica

Subjects
materials science
Abstract

This special issue of the Journal of Thermal Spray Technology presents a selection of articles that were delivered at the International Thermal Spray Conference 2019 (ITSC 2019), which were expanded into full-length, peer-reviewed articles. The conference was held in Yokohama, Japan, on May 26-29, 2019, and was organized by the ASM International Thermal Spray Society (TSS) and the Japanese Thermal Spray Society.

Published
2020

42. Editorial

Author

Marple, Basil R., Agarwal, Arvind, Hyland, Margaret M., Lau, Yuk-Chiu, Li, Chang-Jiu, Lima, Rogerio S., McDonald, André, and Toma, Filofteia-Laura

Published
2013
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43. Development and Application of Binary Suspensions in the Ternary System Cr2O3-TiO2-Al2O3 for S-HVOF Spraying

Author

Potthoff, Annegret, Kratzsch, Robert, Barbosa, Maria M., Kulissa, Nick, Kunze, Oliver, Toma, Filofteia-Laura, and Publica

Subjects
Al2O3-TiO2, suspension spraying, binäre Suspension, binary suspension, Cr2O3-TiO2, Suspensionsspritzen, S-HVOF
Abstract

Next to ZrO2, compositions in the system Cr2O3-TiO2-Al2O3 are the most used ceramic materials for thermally sprayed coating solutions. Cr2O3 coatings present good sliding wear resistance, Al2O3 coatings show excellent insulation behaviour and TiO2 striking corrosion properties. In order to combine these properties, coatings containing more than one oxide are highly interesting. The conventional spraying process is limited to the availability of binary feedstock powders with defined compositions. The use of suspensions offers the opportunity for tailor-made compositions: within the triangle of Cr2O3-TiO2-Al2O3 each mixture of oxides can be created. The formulation of binary or ternary suspensions is based on the preparation of stable single-oxide suspensions, which will later be mixed to achieve the desired composition. This procedure requires the development of water-based suspensions with suitable behavior, otherwise the ceramic particles and dissolved organic additives may interact and form agglomerates, which are prejudicial to the thermal spray process. This work presents criteria for the selection of raw materials as well as relevant aspects for the development of binary suspensions to be used in thermal spray. For procedure validation, coatings sprayed using Cr2O3-TiO2 suspensions and S-HVOF will be shortly presented and analysed in terms of their microstructure and microhardness.

Published
2017

46. Thermisches Spritzen mit Suspensionen: neuartige, wirtschaftliche Hartmetall-basierte Suspensionen.

Author

Toma, Filofteia-Laura, Meyer, Anja, Kunze, Oliver, Potthoff, Annegret, Mayer, Markus, and Pötschke, Johannes

Subjects
METAL spraying, RAW materials, SURFACE coatings, CARBIDES, HARDWARE
Abstract

Copyright of Thermal Spray Bulletin is the property of DVS Media GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2023

47. Entwicklung wirtschaftlich effizienter Hartmetallbeschichtungslösungen für Hochtemperaturanwendungen. Teil 2: Einfluss von Wärmebehandlungen und tribologische Untersuchungen

Author

Berger, Lutz-Michael, Trache, Richard, Toma, Filofteia-Laura, Thiele, Sven, Norpoth, Jonas, Janka, Leo, and Publica

Subjects
Cr3C2-NiCr, Hartmetallschichten, Erosion, Wärmebehandlung, thermisches Spritzen, HVAF, HVOF, Abrasion
Abstract

Ziel der hier vorgestellten Arbeit war es den Einfluss der Beschichtungspulvereigenschaften und der Spritzprozesse auf das technische Leistungsvermögen hochgeschwindigkeitsflammgespritzter Cr3C2-NiCr-Schichten und die Wirtschaftlichkeit bei ihrer Herstellung zu untersuchen und darauf aufbauend zu verbessern. Im hier vorliegenden zweiten Teil werden der Einfluss von Wärmebehandlungen sowie die Beständigkeit im Abrasions- und Erosionsverschleiß diskutiert. Zur Verbesserung dieser tribologischen Eigenschaften muss der Anteil der in der Bindermatrix gelösten Carbide möglichst gering sein, um ihre Versprödung und damit Rissanfälligkeit zu vermeiden. Dies kann entweder durch die Verringerung der Prozesstemperatur und Erhöhung der Partikelgeschwindigkeit beim Spritzen gewährleistet werden, oder aber durch eine nachträgliche Wärmebehandlung der Schichten. Die Untersuchungen haben gezeigt, dass WC-haltige Zusammensetzungen das Kriterium einer gleichzeitigen Verbesserung der technischen Gebrauchseigenschaften der Schichten und der Wirtschaftlichkeit bei ihrer Herstellung erfüllen und noch erhebliches Potential für weitere Verbesserungen bieten.

Published
2016

49. Structure property relationship of suspension thermally sprayed WC-Co nanocomposite coatings

Author

Ahmed, Rehan R., Faisal, N.H., Al-Anazi, Nayef, Al-Mutairi, S., Toma, Filofteia-Laura, Berger, Lutz-Michael, Potthoff, Annegret, Polychroniadis, E.K., Sall, M., Chaliampalias, D., Goosen, Mattheus F.A., and Publica

Subjects
nanoindentation, suspension spraying, WC-Co coating, tribology, nanostructured coating
Abstract

Tribomechanical properties of nanostructured coatings deposited by suspension high velocity oxy-fuel (S-HVOF) and conventional HVOF (Jet Kote) spraying were evaluated. Nanostructured S-HVOF coatings were obtained via ball milling of the agglomerated and sintered WC-12Co feedstock powder, which were deposited via an aqueous-based suspension using modified HVOF (TopGun) process. Microstructural evaluations of these hardmetal coatings included transmission electron microscopy, x-ray diffraction, and scanning electron microscopy equipped with energy dispersive x-ray spectroscopy. The nanohardness and modulus of the coated specimens were investigated using a diamond Berkovich nanoindenter. Sliding wear tests were conducted using a ball-on-flat test rig. Results indicated that low porosity coatings with nanostructured features were obtained. High carbon loss was observed, but coatings showed a high hardness up to 1000 HV2.9N. S-HVOF coatings also showed improved sliding wear and friction behavior, which were attributed to nanosized particles reducing ball wear in three-body abrasion and support of metal matrix due to uniform distribution of nanoparticles in the coating microstructure.

Published
2015

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